Error 500 After Join.php is executed

Hi All

iam getting a very strange error here

During the join process once you press submitt i get an error 500 but the user is anyways registered and the email is sendt out to him to.

Where could the problem be?

This error is caused probably from a installation of third-party module that is not compatible with dolphin 7.1 example one of my client have this problem for having installed this module http://www.boonex.com/m/dolphin-social-publisher

check if you have this module or other modules installed where it has been declared the compatibility with dolphin 7.1

I have the Social Plugin installed to will test it thanks

 Sorry it is in the modul section but not installed. BTW iam Running 7.0.9. not 7.1 ;)

I will remove most third party option now an check them again.