New-PSdrive fails in script, works at command line

Question

If I RDP to ServerA (2008R2) as userB (Domain User) and open a PS (2.0) command window, I can successfully run:
New-PSdrive -Name "X" -PSProvider FileSystem -Root "\\MYSERVER\MyShare"
But if I RDP to ServerA and launch c:\scripts\myscript.ps1 from a PS window (myscript contains the same line of code), drive X: is not mapped!
Does the script run under different permissions?  Permissions on folder c:\Scripts are wide open: Everyone = Full Control.  The Scripts folder needs to reside in a location where all users can access it.
How do I get New-PSdrive to work in myscript?
thx

Answer 1

Thanks for the reply.  I will explore help for get-executionpolicy.
As for the rest of the script, it's only that line for mapping a drive and then calling Robocopy.
Below are results of a test I ran.  If I map the drive first, the script runs fine.  But if I delete the mapped drive, I cannot get New-PSdrive to remap it... at least not in the script.  If I run the command in a PS window, as mentioned before,
New-PSdrive works fine.
PS C:\Users\userB> net use X: \\MYSERVER\myshare
The command completed successfully.
PS C:\Users\userB> net use
New connections will be remembered.
Status Local Remote Network
OK X: \\MYSERVER\Myshare Microsoft Windows Network
The command completed successfully.
PS C:\Users\userB> C:\scripts\myscript.ps1
Name Used (GB) Free (GB) Provider Root
X FileSystem \\MYSERVER\Myshare
ROBOCOPY :: Robust File Copy for Windows
Started : Thu Jul 25 13:07:59 2013
Source : X:\path\dir\
Dest : C:\Users\userB\dir\
Files : *.*
Options : *.* /TEE /COPY:DAT /XA:SH /R:1 /W:1
1 X:\userB\dir\test.txt
*EXTRA File 0 shortcut.lnk
Total Copied Skipped Mismatch FAILED Extras
Dirs : 1 0 0 0 0 0
Files : 1 1 0 0 0 3
Bytes : 0 0 0 0 0 1.4 k
Times : 0:00:00 0:00:00 0:00:00 0:00:00
Ended : Thu Jul 25 13:07:59 2013
PS C:\Users\userB> net use * /del /yes
You have these remote connections:
X: \\MYSERVER\myshare
Continuing will cancel the connections.
The command completed successfully.
PS C:\Users\userB> C:\scripts\myscript.ps1
Name Used (GB) Free (GB) Provider Root
X FileSystem \\MYSERVER\Myshare
ROBOCOPY :: Robust File Copy for Windows
Started : Thu Jul 25 13:09:45 2013
2013/07/25 13:09:45 ERROR 3 (0x00000003) Getting File System Type of Source X:\userB\dir\
The system cannot find the path specified.
Source - X:\path\dir\
Dest : C:\Users\userB\dir\
Files : *.*
Options : *.* /TEE /COPY:DAT /XA:SH /R:1 /W:1
2013/07/25 13:09:45 ERROR 3 (0x00000003) Accessing Source Directory X:\path\dir\
The system cannot find the path specified.