Corrupted installer after signing

After signing my setupfile, the setup quits with the error message "Error decompressing data! Corrupted installer?". Without Signature, everything works fine.

Does anybody know, how to handle that problem?
(CRCCheck is off)

Thanks a lot!

How are you signing? Are you using signtool?

Stu

We are signing with Microsoft SignTool.

Command: signtool sign /ac C:\_Codesigning\MSCV-VSClass3.cer /sha1 XXX /t http://timestamp.verisign.com/scripts/timstamp.dll /v