Up to & including 2003 a database would be a mdb (or a compiled version that you can't amend as a mde. Access 2007 has introduced new file formats (accdb and accde). It will, however, run Access 2003 mdb's in that format.
To fix the libraries, open the mdb in 2007 while holding down the shift key. This should open the database without running and macros or code. Goto the modules part and open any module. The VBA window will open. Goto the Tools > References and check if any ticked libraries are missing. If so, note their names and deselect them. Then close references and re-open. Scroll the list and finmd them and tick them again. When all are done, close the references window & compile the database. This should fix it.