possible security problem?

[eluser]n0xie[/eluser]
It is most likely an automated script that checks for the presence of phpmyadmin on several domains and ips in order to maybe exploit it (if it's an older, unsecure version). If you monitor your requests you will most likely see some requests like this also targeted at specific CMS'es (Joomla is a popular target). Wether your site is specifically targeted I cannot say, but seeing as there are only these entries in your logs I would guess this is more of a 'generic' type of attack.

Still wouldn't hurt to be careful, and maybe start logging some more and/or paying close attention to the specific server.