Weird .Net app compression problem

i m making a small .net compressor, while after i added a small decompressor section in the end of the pe file, while after everything is done, the system reports "Strong name validation failed for assembly
'C:\test\my.exe'. The file may have been
tampered with or it was partially signed but not fully signed with the correct
private key."

It is really weird, because i did not add any strong name in the exe
any guys met the same problem?