Yep, I did.
Same error :-(

>Did you try to call the method w/o any parameter?
>
>>Just tried but no change. I'm still getting an unknown com status code. (See attachment)
>>
>>>WAG, try to use an object type null variable
>>>

>>>if llError 
>>>    loSession = CREATEOBJECT("Empty")
>>>    loSession = NULL
>>>    lnErrorCode = loThirdParty.getLastErrorCode(loSession)
>>>endif
>>>

>>>
>>>BTW, it's totally unnecessary to compare logical values with .T./.F.
>>>
>>>>I'm accessing a third party dll which has a getLastErrorCode-method.
>>>>After initiliazing the object, I have to begin a new session.
>>>>If I can't establish a session, i want to retreive the last error code. This method has the session-object as an incoming parameter but when i don't have this object, the parameter can be set to NULL.
>>>>When I do this in Visual Studio I send 'null' to the method and it works fine, BUT in VFP any value I send works (NULL, .NULL., "", .F., 0, ...) I always get a 'Unknown COM status code'.
>>>>
>>>>Does anyone know what value to send ?
>>>>If i have established a session and i send this session-object as the parameter an errorcode is returned.
>>>>
>>>>------------------------------
>>>>
>>>>loThirdParty = CREATEOBJECT("CISComWrapper.CIS_ComWrapperImpl")
>>>>
>>>>llError = .F.
>>>>try
>>>> loSession = loThirdParty.BeginSession()
>>>>catch
>>>> llError = .T.
>>>>endtry
>>>>
>>>>if llError = .T.
>>>> lnErrorCode = loThirdParty.getLastErrorCode( NULL ) &&& this is the parameter I'm talking about
>>>>endif
>>>>
>>>>loThirdParty = NULL