gpg run from .procmailrc can't find secret keyring

[Joseph Shraibman]

I'm running:
gpg (GnuPG) 1.0.7


I set up a script to be called from my .procmailrc to decrypt incoming pgp mail, but it 
doesn't work. I put in my script to call gpg --list-secret-keys and here is the output:
gpg: Warning: using insecure memory!
gpg: [don't know]: invalid packet (ctb=00)
gpg: read_keyblock: read error: invalid packet
gpg: enum_keyblocks(read) failed: invalid keyring

I have no problem running gpg --list-secret-keys from the command line. What is going on?
I can run md5sum on my .gnupg/secring.gpg  so the file can be read.