Error with the cache

[Solid Orphan]

Hello,
Sorry for my bad english.
I had a forum on phpbb3 and I succesfully convert to smf RC5.
But when I navigate on it, I have a error sometime:

Code Select Expand

Warning: require(/www/forum/cache/data_cbf89d48adfc6d580979d4b17264fcc9-SMF-modSettings.php) [function.require]: failed to open stream: No such file or directory in /www/forum/Sources/Load.php on line 2710

Fatal error: require() [function.require]: Failed opening required '/www/forum/cache/data_cbf89d48adfc6d580979d4b17264fcc9-SMF-modSettings.php' (include_path='.:/usr/local/lib/php') in /www/forum/Sources/Load.php on line 2710

What must I do?

Thanks.