I'll try to install AdminTools pro and see if it's stopping anything (maybe I'll try to get in touch with Nicholas, too).
>> You will not get Nicholas available till next Oct. 23 +/- (He is attending a Joomla! Conference right now)
Before the move, everything was working?
>> No all of them as reported before on other post:
-The Old VPS was build with PhP under 'Apache_module' and the reason to move to the new one to CGI/FastCGI under fcgid_module to obtain the same user under joomla! and under the site owner (allowing to keep restricted CHMOD permissions with no one over 755 for directories and 644 for files). On the older VPS some sites worked correctly but those sites are not working now running inside the new VPS. The other change is the AdminTools 2.4.0 upgrade. I don't see any reason why the mentioned configuration could stop the plugin to work...!?... Perhaps, this info. may help you!
Maybe we'll consider using another format instead of XML, but I'll need more investigation.
>> Sounds good!... May be, whe you get you 'next wersion with debugging feature, you may wish to have a double side 'Joomla! 2.5.7 installations, one were to install a 'tracktime' component and other where to install the plugin inside the same servers the others (I hope that could help you to see the problem closely)
Arrived the momment, just email me dorectly (you already have my emaill address) and I'll be very happy to build both temporal sites for your test.
I'll stay tuned to your next input / feedback,