Symptoms
When you access an Array field of a structure that is defined in .NET from inside a COM DLL, you may receive the following error message:

“An unhandled exception of type ‘System.ArgumentException’ occurred in ProjectName”
Additional information: Wrong number of arguments or invalid property assignment.
Resolution
Because of the late-bound method that is used in this case, the Visual Basic 6.0 runtime cannot get the type information for the Array field that you are attempting to access.