Hi, I think some people had problems, when they tried to go back to Nar Shaddaa after they had finished the planet (1/3 load bug when leaving the Ebon Hawk).
I had the same problem, the only way I found to avoid it was NOT to go back to Telos immediatley after Nar Shaddaa, but to finish another planet first. After that you should be able to travel all planets without major problems.
For further questions or explanations (I know, my English is quite bad :D), send me a mail.
greez, Cato