I am running UBB.classicâ„¢ 6.7.3

Suddenly today I got this error:

Script:
Line#:
SQL Error: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
Please verify that your MySQL server is running
SQL Error #: 2002
Query: Unable to connect to the database!

Going to the backend I got this error:

StandardHTML stack trace:
at /home/cluster1/data/h/s/a1332841/html/ubb/Templates/cp2_common.pl line 96

main::StandardHTML called at /home/cluster1/data/h/s/a1332841/html/ubb/Templates/cp2_common.pl line 131

main::StandardHTML2() called at /home/cluster1/data/h/s/a1332841/cgi-bin/cp2_lib.cgi line 756

main::CatchException() called at cp.cgi line 492

main::__ANON__() called at Modules/Error.pm line 303

eval {...} called at Modules/Error.pm line 294

Error::subs::run_clauses() called at Modules/Error.pm line 386

Error::subs::try() called at cp.cgi line 493


Extra information:

Can't EXlock '/home/cluster1/data/h/s/a1332841/html/ubb/cache-ZPKTTRJB/lock/global.cgi'.

The operating system has run out of file locks to give me.

Please ask the administrator to contact the web hosting provider.

The exact error returned by the operating system is:
No locks available


The hosting company has no idea what is wrong, and neither do I.

For weeks we had been getting a sporadic error:

"No input file specified."

Any help on where to start or what to tell the hosting company?

Thanks.

Oh, the site is http://www.belizeforum.com