[imp] GPG shows "Bad Signature"

[Michael Wisniewski]

Hi!

I'm trying to setup IMP to encrypt and sign messages.  I've sent a test 
message to myself with it being signed and encrypted.  When opening the 
message, I get the following....

gpg: Signature made Tue 26 Mar 2013 03:25:59 PM CDT using RSA key ID 
48EDE6D1
gpg: BAD signature from "Michael Wisniewski <wisniewski at mwiz.org>"

When looking at the same message within Thunderbird, it seems to 
decrypt it just fine and not give me any warnings.  Does anybody happen 
to know how to resolve this problem?

Thanks!