Just had UBB.threads installed. It worked briefly. I made a few changes to general options that didn't change critical items already set up by the installer. Now when I try to access forums I get an error message that says "No input file specified." I am dead in the water. What did I do?

I can see my control panel OK. No access to forums, FAQ, or other functions on the product menu bar.

This turned out to be that the server doesn't handle search engine friendly urls. Working this in a ticket.

Sounds wonderful ;)... i had this happen on a clients site which was running really anal securty settings :/...

I have been getting this error "No Input File Specified" increasingly and intermittently during the last week. I am running UBB.threads™ 7.3.1 on a linux server. What was the solution to this problem?

did you turn off SE friendly URLs just to see if that 'works' ?

There was a reported bug around that version that was corrected later on.
It was a simple edit in a couple of template files I believe.

what function are you using when you get that error.
A hint to the file will be in the url of the browser.

I have reports that it happens intermittently but some users have reported getting the error repeatedly, regardless of what page they are accessing, for over 15 minutes. So it does not seem to be restricted to a certain page. And it just started, the software ran fine for months without a problem. This makes me think it might be an incapatibility with the server software? Just thought others might of had this problem and found the solution.

Well it was not just paging through the forum it was as I recall when submitting a form such as adding a post or reply.
So this may not apply.

Were any server updates done about the time this started happening?

They did not make us aware of any updates. But I will submit a trouble ticket to find out and report back.

Well, most webhosts don't keep users up to date on when they update things... in fact, some just cron yum to run every week so they might even not know an update ran...