C# dll in orchestration and corrupt data

BizTalk 2010 EDI
When you drop one transaction it looks good when you drop many the data is corrupt.
If you use c# and static variables or methods. It works fine with one transaction, but when you post many transactions the static variables occur once. The data is not isolated and you en up with a mess.

You need to write the DLL with one class and do not use static variables or Methods.

Been a while since I posted