[Harper Agent class levels doesn't aplies to sorcerer levels]

I made a build in Mask of the Betrayer :

3 levels Swashbuckler

2 levels Sorcerer

5 levels Harper Agent

Then I try to make a level of Eldritch Knight, and when I must select the feat of Sorcerer (to continue levels of Sorcerer with Eldritch Knight), but there are not skills to choice.

I tryed to do it with, after the 5 levels of Harper Agent, taking some levels of Sorcerer but I can only do it well if I reached 6 levels of Sorcerer (doesn't matters the Harper Agent levels).

¿Am I doing something wrong? ¿is an error? ¿there is some patch for this error?

Thanks.