it could be very helpful class.
1. is $this->sys private access variable? It should be $this->_sys in this case
2. Each method (like getAppData(), getDesktop(), etc.) looks similar to others. In each of these methods you have defined an array and each method contains foreach. Im sure it can be refactored and some repeated code can be moved to private methods. After that you should have shorter code :)
3. you should move array with language data to begin of file or to separate config file. It could not be mixed with php code
4. please think if it is possible to add getting php and pear directories. it can be also helpful.