Did you meet all the Jedi Masters?
Vrook on Dantoine, Kavar on Onderon, Zez Kai Ell on Nar Shadaa and Vash (She's dead and can be found in the academy, not in the secret tomb. The secret tomb is optional and is opened only to lvl 9 + chars that are either 75 % LS or DS) on Korriban ?
If so, did you talked to Kreia?
She has to tell you that it's time to return to Dantoine