iRule seems to block page request

Found at least one of your issues. You don't have a space between the second "findstr" and "[HTTP::uri]". The TCL processor is trying to run the command "findstr[HTTP::uri]" which throws a runtime exception that you should see in the /var/log/ltm file.

I've got an alternative for your iRule that should work and speed things up a bit.

when HTTP_REQUEST {  
   switch [findstr [HTTP::uri] "webctid=" 8 2] { 
     "83" - 
     "95" { 
       log local0. "Found match, redirecting to maintenance page..." 
       HTTP::redirect "http://distance-ed.bcc.ctc.edu/bbmaint.asp" 
     } 
   } 
 }

This avoids the multiple parsing by calling findstr twice and easily allows for new webctid's in the future.

Let me know if this does or doesn't work.

-Joe