Procmail: Program failure

Procmail was working fine and dandy. Then, I enabled WebMail in Server Admin (I know SA restart bad mistake). Now, all incoming mail being filtered through Procmail is not reaching user's inboxes.

I get the following info in the mail.log when messages attept to make it to Cyrus' deliver program:

Aug  7 07:25:22 xserve postfix/pipe[25243]: 987AB394052: to=<jjones@domain.com>, orig_to=<jeff@domain.com>, relay=procmail, delay=4, status=deferred (temporary failure. Command output: procmail: Couldn't read "/Users//.procmailrc" procmail: Program failure (65) of "/usr/bin/cyrus/bin/deliver" )

I noticed that the user name doesn't appear in the error "/Users//.procmailrc". This made me think that my transport in master.cf was bungled somehow.

I've checked and double-checked main.cf and master.cf files and they are correct. I've restarted Postfix. Still the same error.

Any advice is much appreciated.