Spoke to soon - Got the problem again but I don't know if it is the same one -

Error Occurred While Processing Request

Error Diagnostic Information

An error occurred while evaluating the expression:

(len(trim(FORM.UserName)) gt 0) and ((left(FORM.Subject,3) is not "RE:") and (FindNoCase("http:", FORM.body)) or ((len(FORM.body) - len(replacenocase(FORM.body,"http:","","ALL"))) gt 10) or (FindNoCase("sites", FORM.Subject)) )

Error near line 21, column 38.

Error resolving parameter FORM.USERNAME

The specified form field cannot be found. This problem is very likely due to the fact that you have misspelled the form field name.

The error occurred while processing an element with a general identifier of (CFIF), occupying document position (21:1) to (21:234) in the template file d:\!webserver\mudcat\htdocs\ThreadNewMess-Sub.cfm.

Date/Time: 02/17/10 11:10:57
Browser: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.2) Gecko/20100115 Firefox/3.6 (.NET CLR 3.5.30729)
Remote Address: 194.106.220.83
HTTP Referrer: http://mudcat.org/thread.cfm?threadid=127418&messages=6