SEHException While Enlisting Orchestration

I am posting one of the errors we encountered over which considerable time was spent debugging.

You will get the below Error in Event Log


Event Type: Error
Event Source: XLANG/s
Event Category: None
Event ID: 0
Date: 5/5/2005
Time: 3:22:32 PM
User: N/A
Computer: Machine12

Description:
An SEHException exception occurred while the XLANG/s runtime enlisted a service.
Error message:External component has thrown an exception.
Call stack: at Microsoft.BizTalk.MetaDataOM. ICLRType.GetFields(UInt32 dwBindingFlags) at Microsoft.BizTalk.XLANGs.BTXEngine. BTXServiceStaticState._createStringLookup(String svcFullTypeName,
IAssemblyManager asmMgr) at Microsoft.BizTalk. XLANGs.BTXEngine.BTXServiceStaticState. PersistState (String mgmtDBServer, String mgmtDBName, String MsgBoxGroupName, String ApplicationName, String serviceAssembly, String serviceTypeName, Guid[] PortIDs, Guid[] LrpIDs, ITransaction transaction)
at Microsoft.BizTalk.XLANGs. BTXEngine. BTXService.GoLive (String configDBServer, String configDBName, String msgBoxGroupName, String applicationName, String servicePath, String serviceTypeName, Guid[] portIDs, Guid[] lrpIDs, ITransaction transaction)

Exception type: BTXEnlistmentException
Source:
Target Site:
Help Link:
Additional error information:

External component has thrown an exception.

Exception type: SEHException
Source: Microsoft.XLANGs.BizTalk.Engine
Target Site: System.Collections.IEnumerator GetFields(UInt32)
Help Link:
Additional error information:

This normally occurs when you don't have a dependent file of the assembly not in GAC . That is an orchestration which references other Dll's must have the dependencies already GAC'd

Another variation of this enlistment error is OutOfMemory exception which is due to some limitation of WMI , which can be increased with a custom Script


But in our case this was not the case I checked and rechecked the dependencies of our project they were all there .

What we found out was that our Production server did not have Biztalk SP1 applied whereas the dev machine had SP1.

So apparently the issue is still I guess of DLL's Missing in GAC but not of the application but that of Biztalk Later version Assemblies !!