May be unrelated but it doesn't crash immediately and in those few seconds if I move the window it updates the frame and I see my form, partially at least.
Isn't it suppose to be embedding the form controls into the task window not just showing the form I created?
Like seen here in the sample: http://help.solidworks.com/2014/english/api/epdmapi/SetupPageResult.png
Finally coming back to this I found the solution. Posting to get the answer on here in case anyone else comes across this issue.
I was on the right track with the form controls being the source of the problem.
I was using a Windows Form, turns out because the custom pages are being hosted by the task window you must create your controls on/as a User Control.
Now that I got that sorted finally I can start debugging the actual task -.-