Error in postfix/nqmgr

First off, I am very new to this....
I have a couple of error messages popping up in my maillog:

Apr 9 14:17:46 srv01 postfix/nqmgr[19320]: warning: connect to transport /etc/procmailrc: No such file or directory
Apr 9 14:17:46 srv01 postfix/nqmgr[19320]: warning: connect to transport /usr/bin/spamc: No such file or directory

But both these directories DO exist, I have tried changing ownership and permissions to no avail.

These 2 messages reccur every minute at the same second whether the mail server is processing mail or not.

I know how this happened. The other day in the spirit of "Sort it out yourself, webmin is a Good Tool" I decided to try and get my non working spamassassin sorted. In webmin ->servers ->Postfix config ->General options I went to the bottom of the page and in the last box, "email content filter" (Help topic on this link not working :-( ) I entered the path to spamassassin. This didnt make it work so I deleted the path, and tried the path to procmail in that field instead. This didnt work either so I deleted that out too and went back to head scratching... When I looked at the maillog I saw the above errors, starting from that time referring to the two paths I had entered and then deleted. Has Webmin in my incompetent hands broken it?

I went into /etc/postfix/main.cf, but no mention of spamc or procmail. Same thing at /etc/postfix/master.cf I had a good browse around but cannot find any other clues as to what is causing this. No doubt you will know instantly on seeing this log and be able to point me to the file I need to edit! That would be a great help.