No, a search function wont be any good.
You need to read the registry settings of Plus!. From these settings you can build the proper and complete path:
HKCU\Software\Patchou\Messenger Plus! Live\
your@email.com
LogsDirectory, LogsInDateDir, LogsDateDirFormat
You also need to read the user's local translations and abbreviations for date names like months and days. For this you need to use some Windows APIs like
GetLocaleInfo or
GetDateFormat.
http://www.msgpluslive.net/help/registry/
http://www.msdn.com/