PowerShell script : Directory object not found error in Get-ADGroupMember

Question

I am new in powershell scripting. I am writing a script to add users in different AD Groups. while doing so I do the following:
Check if the user already exist in the group:
$mbr_exist = Get-ADGroupMember $grpname | Where-Object {$_.SamAccountName -eq $sam}
If user does not exist then add the user to the group.
When I manually run the script its runs flawless, without any errors. But when I schedule the script to run it gives an error as follows:
3/30/2015 8:32:15 AM Directory object not foundAt + $mbr_exist = Get-ADGroupMember $grpname | Where-Object {$_.SamAc ... + ~~~~~~~~~~~~~~~~~~~~~~~~~~ Error at Line:$mbr_exist = Get-ADGroupMember
$grpname | Where-Object {$_.SamAccountName -eq $sam}
The strange thing is the user for which it throws the error is present in the group.I am not sure why this error is occurring when scheduled. Can any one please help? All the suggestions will be appreciated
Note: (The script is scheduled using Windows Task Scheduler)
try
# # Initialize the variables we will use
$status = 'false'
$drivename = "H:"
$sysdate = Get-Date -UFormat "%m_%d_%Y"
$foldername = $drivename + "\Script_Result\PowershellData"+ $sysdate
$backup_folder = "$foldername\AD_Groups_Backup"
$updatedGroup = "$foldername\Updated_AD_Groups_LogFiles"
$LogFilePath = "$foldername\Log_Update_ADGroups"+$sysdate+".log"
# # Initialize the arrays we will use
$GroupArray = @()
# # maintain log of program startup
$logdate = get-date
$logdate.ToString() + "`tStarted script to Update AD user Groups..." | Out-File -FilePath $LogFilePath
# # Create a sub folder to store the backup files
$fileexist = Test-Path $backup_folder -PathType Container
if($fileexist -ne 'False')
New-Item -ItemType Directory $backup_folder
# # Create a sub folder to store Updated AD group Log files
$fileexist = Test-Path $updatedGroup -PathType Container
if($fileexist -ne 'False')
New-Item -ItemType Directory $updatedGroup
# # Take back up of the AD groups data
Get-ADGroupMember -Identity "Group1" | Export-csv "$backup_folder\Group1_BackUP$sysdate.csv"
Get-ADGroupMember -Identity "Group2" | Export-csv "$backup_folder\Group1_BackUP$sysdate.csv"
Get-ADGroupMember -Identity "Group3" | Export-csv "$backup_folder\Group1_BackUP$sysdate.csv"
Get-ADGroupMember -Identity "Group4" | Export-csv "$backup_folder\Group1_BackUP$sysdate.csv"
(an so on..... 11 such groups )
# # Fetch AD Users data
$ADusers = Get-ADUser -filter {(EmployeeNumber -gt 1) -and (EmployeeNumber -ne "N/A") -and (Enabled -eq $true)} -Properties * | Sort-Object -Property EmployeeNumber
$ADusers.Count
foreach($u in $ADusers)
$sam = $u.SamAccountName
$empnum = $u.EmployeeNumber
$mgr = $u.mgr
$fsal = $u.'fsalary-Hourly'
$comp = $u.Company
$ofc = $u.Office
Write-Host "$sam : $empnum : $mgr :$fsal : $comp : $ofc" -ForegroundColor Yellow
$GroupArray = @()
# # Check if the user fits in any of the 11 scenarios
if($comp -eq "US")
# scenario 7
write-host "7. Add to US Employees"
$GroupArray += "US Employees"
if($mgr -eq "Y")
Write-Host "1. ADD to US MAnagers"
$group = "US Managers"
$GroupArray += $group
if(($fsal -eq "Hourly") -and ($ofc -ne "Canton"))
Write-Host "3. Add to US Hourly (excluding Canton)"
$group = "US Hourly (excluding Canton)"
$GroupArray += $group
if(($fsal -eq "Hourly") -and ($ofc -eq "Canton"))
write-host "4. Add to US Canton Hourly"
$group = "US Canton Hourly"
$GroupArray += $group
if(($fsal -eq "Salaried") -and ($ofc -eq "Corporate" -or $ofc -eq "Landis Lakes 1" -or $ofc -eq "Landis Lakes 2"))
Write-Host "5. Add to US Salaried Corporate"
$group = "US Salaried Corporate"
$GroupArray += $group
if(($fsal -eq "Salaried") -and ($ofc -ne "Corporate" -and $ofc -ne "Landis Lakes 1" -and $ofc -ne "Landis Lakes 2"))
Write-Host "6. Add to US Salaried Plant"
$group = "US Salaried Plant"
$GroupArray +=$group
elseif($comp -eq "canada")
# scenario 9
write-host "9. Canada Employees"
$GroupArray += "Canada Employees"
if($mgr -eq "Y")
Write-Host "2. Add to Canada Managers"
$group = "Canada Managers"
$GroupArray += $group
if($fsal -eq "Hourly")
Write-Host "10. Add to Canada Hourly"
$group = "Canada Hourly"
$GroupArray += $group
if($fsal -eq "Salaried")
Write-Host "11. Add to Canada Salaried Plant"
$group = "Canada Salaried Plant"
$GroupArray += $group
elseif($ofc -eq "Corporate" -or $ofc -eq "Landis Lakes 1" -or $ofc -eq "Landis Lakes 2")
Write-Host "8. Add to Corporate Employees"
$GroupArray += "Corporate Employees"
write-host "Final Group List" -ForegroundColor Green
$grplen = $GroupArray.Length
#$GroupArray
$grplen
for($i= 0; $i -lt $grplen; $i++)
$grpname = $GroupArray[$i]
write-host "$sam will be added to Group : $grpname" -ForegroundColor Magenta
# # Check if the user is already present in the Group
$mbr_exist = Get-ADGroupMember $grpname | Where-Object {$_.SamAccountName -eq $sam}
if($mbr_exist -eq $null)
# #Add user to US Managers group
Add-ADGroupMember -Identity $grpname -Members $sam
Write-Host "1. User $sam is added to $grpname group" -ForegroundColor Green
# # documenting the user list that are added to this group
$grpmbr = New-Object PSObject
$grpmbr | Add-Member -MemberType NoteProperty -Name "EmployeeNumber" -Value $empnum
$grpmbr | Add-Member -MemberType NoteProperty -Name "SamAccountName" -Value $sam
$grpmbr | Add-Member -MemberType NoteProperty -Name "Name" -Value $u.Name
$grpmbr | Add-Member -MemberType NoteProperty -Name "DistinguishedName" -Value $u.DistinguishedName
$grpmbr | Add-Member -MemberType NoteProperty -Name "mgr" -Value $mgr
$grpmbr | Add-Member -MemberType NoteProperty -Name "Company" -Value $comp
$grpmbr | Add-Member -MemberType NoteProperty -Name "Salary/Hourly" -Value $fsal
$grpmbr | Add-Member -MemberType NoteProperty -Name "Office" -Value $ofc
$grpmbr | Add-Member -MemberType NoteProperty -Name "ADGroup" -Value $grpname
$grpmbr | Export-Csv "$updatedGroup\ADUsers_To_Group($grpname)_$sysdate.csv" -Append -NoTypeInformation
else
Write-Host "Member $sam already exist in $grpname group" -ForegroundColor Red
$logdate = get-date
$logdate.ToString() + "`tCompleted script to Update Update AD Groups..." | Out-File -FilePath $LogFilePath -Append
$status = 'true'
return $status
catch
$err_lineno = $error[0].InvocationInfo.ScriptLineNumber
$err_line = $error[0].InvocationInfo.Line
$ExceptionMessage = $_.Exception.Message
#$ExceptionMessage
$error_info = $error[0].ToString() + $error[0].InvocationInfo.PositionMessage
Write-Host "$error_info " -ForegroundColor Red
$FailedItem = $_.Exception.ItemName
if($ExceptionMessage)
$logdate.ToString() + "`t $error_info " | out-file "$foldername\ErrorLog_Update_AD_Groups$sysdate.log" -append
"Line Number: $err_lineno . `nError at Line: $err_line" | out-file "$foldername\ErrorLog_Update_AD_Groups$sysdate.log" -append
#Invoke-Item "C:\ErrorLog.log"
$status = 'false'
return $status

Answer 1

Hi mdkelly, Sorry for such a late reply (due to credential issues).
I am using Windows task scheduler to schedule the task. I am given the administrator access to the server (Windows Server 2012). So I think I set to run the script under system account.
My apologies for asking this, am I missing something while scheduling the script through task scheduler?  how to check if the scheduled task is running under who's credentials? How to pass my (admin) credentials, so that the script execution won't face
a problem? Any suggestion on the above questions will be helpful. (I tried to search on net for the questions but didn't get any conclusive answers)  
Thanks in advance.