Recently discovered 2 bugs related to XMAP component. Bug is the same, but it is related to 2 different components.
1. SobiPro invisible in admin area
2. VirtueMart invisible in admin area
Bug appear with combination of Joomla 2.5 with XMAP installed.
The fastest solution is to delete respected plugin of XMAP, for instance XMAP for SobiPro and XMAP for VirtueMart.
After that reinstall SobiPro or VirtueMart and respective components will be visible again.