Segmentation fault after upgrading to CI 2.1.3

[eluser]Unknown[/eluser]
i am try to upgrade my application from CI 1.7 to 2.1.3 but i got a segmentation fault. after some debugging i found that the script crash during include a helper.
my helper inlcude only functions which i use inside my app. I can't figure out why it crash during including a file?
does any one has an Idea?

thanks