InfoPath combined with Excel Rest services gives State service error

Question

Hi
I'm having a problem with InfoPath and Excel Services. I have a InfoPath form that calls Excel to do a fairly simple calculation, but I also have another form at a client that is doing the same calling a much more complicated function.
The error I get is
SharePoint Server
State Service
bm1k
Medium
StateSqlSession.GetItemBytesInternal() Locked row in database for key ba18f90ee2e844468b08e90ad96dff2c_05967b71a21948d39b7d4d3ada9b27c9 for 4 seconds
SharePoint Server
State Service
bm0t
Unexpected
StateManager.GetState() Locked data (05967b71-a219-48d3-9b7d-4d3ada9b27c9)
InfoPath Forms Services
Runtime - State Service
b5st
Medium
MOSS StateService threw an exception: A Microsoft SharePoint Server State Service error occurred while processing your request. For more information, contact your server farm administrator.
I have determined that if the user is in the Members group, then it works, but as soon as the user is in another group, it gives the error. I have played around with permission levels, given the user all rights, but it still gives that error.
Does anyone have any idea about what might be the problem? I have thought that it's a problem on the state service, but it isn't configurable. I don't want to resort to put everyone into the Members group, as that doesn't seem to be a solution that will
work with everyone. We are on the June 2012 CU.

Answer 1

Thanks Sergio. I tried that but unfortunately didn't fix the problem. I have given the groups Contribute rights, Full Control rights, create my own custom permission level, nothing works except when the user is in the Members post. 
I realised today that the error I posted above is a bit misleading. The error that happens first before that one is this (after removing timestamps and correlations):
Entering monitored scope (Request (POST:https://<server>/ContentHub/_layouts/Postback.FormServer.aspx))
Name=Request (POST:https://<server>/ContentHub/_layouts/Postback.FormServer.aspx)
Site=/
Access denied.
Thread was being aborted.
Not persisting state for request due to previous errors. Form Template: urn:schemas-microsoft-com:office:infopath:Expense-Claims-With-Excel:-myXSD-2004-12-26T20-14-04
Unhandled exception processing request for PostbackPage Microsoft.Office.InfoPath.Server.Util.InfoPathFatalException: Exception of type
'Microsoft.Office.InfoPath.Server.Util.InfoPathFatalException' was thrown.
at Microsoft.Office.InfoPath.Server.Util.GlobalStorage.get_CurrentFormId()
at Microsoft.Office.InfoPath.Server.Util.GlobalStorage.get_CurrentContext()
at Microsoft.Office.InfoPath.Server.Util.GlobalStorage.IsDefined(GlobalItems key)
at Microsoft.Office.InfoPath.Server.Controls.DateFormattingInfo.TryGetCachedTimeZoneId(UInt16& timeZoneId)
at Microsoft.Office.InfoPath.Server.Controls.DateFormattingInfo.GetSPTimeZoneObject()
at Microsoft.Office.InfoPath.Server.Controls.DateFormattingInfo.CalculateSPLocalTimeOffset()
at Microsoft.Office.InfoPath.Server.Util.GenericUtils.GetServerTimeZone()
at Microsoft.Office.InfoPath.Server.DocumentLifetime.ErrorPageRenderer.RenderResult(TextWriter writer, Document document, EventLogStart eventLogStart)
at Microsoft.Office.InfoPath.Server.DocumentLifetime.ErrorPageRenderer.RenderForException(HttpContext context, Exception exception, Document document, EventLogStart eventLogStart)
at Microsoft.Office.InfoPath.Server.Controls.PostbackPage.OnPreInit(EventArgs e)
at System.Web.UI.Page.PerformPreInit()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
The error I first posed is I think the reaction to this exception. The strange thing is that the user can access the spreadsheet fine. When I go to the URL that is used for the rest service and just remove the $format parameter, it displays it fine as a HTML
value.