Warning... in admin cachestorage

PHP Warning: implode() [<a href='function.implode'>function.implode</a>]: Invalid arguments passed in administrator/components/com_mobilejoomla/cachestorage/file.php on line 267

appeared 9 times for 2 seconds!
no idea what causes it, i have just disabled cache after seeing the error in the log
cpu usage - very very high all the time

joomla 1.5.25
php 5.3.8
mysql 5.1.58

This issue is fixed in svn:
github.com/mobilejoomla/mobilejoomla/commit/71c1f1c9d2da01368ca3d599acd5e64cb97b91a9#cachestorage/file.php

Actually, this warning arises only in the case of using mobile mode in desktop browser.