UBB.threads PHP Forum Software Community Forums UBB.classic UBB.classic 6 Support ERROR message, board ran for 5 years

running version 6.5.0 on www.hardcorewebsite.net (music site). Just got error below and unable to add, respond, edit posts.

I tried to clear cache and rebuild search but didnt solve problem. I tried rebuild forums and got the same error.

Any ideas on a fix ? Would the upgrade work or is this bigger?

An error has occured:

Can't find string terminator "!" anywhere before EOF at CGIPathNonCGI//cache-2J3W43NY/search_index/forum1_recentmeta.cgi line 1823.