Sorry for the delay. We've been trying to recreation this and simply can't on any of our dev sites. I also just looked at your site. The module is inserting the correct variables into the page. Specifically, in the login form, the following input is set:
<input type="hidden" name="option" value="com_comprofiler" />
<input type="hidden" name="task" value="login" />
<input type="hidden" name="op2" value="login" />
<input type="hidden" name="lang" value="dutch" />
<input type="hidden" name="force_session" value="1" />
<input type="hidden" name="return" value="B:aHR0cDovL3BhcnR5LXZlcnZvZXIubmwvZXZlbmVtZW50ZW4="/><input type="hidden" name="cbsecuritym3" value="cbm_6c32f769_25113913_f7d233070a6ce4cd210ae4b558aa583b" />
Those show that the form should be submitted to CB, as expected. The 'return' variable has a value that begins with "B:", which is required by Community Builder to denote that it's a base64 encoded URL. When that URL is decoded, it comes out to:
http://pa.....oer.nl/evenementen, which was the current page I was looking at at the time.
So, everything seems right to me from the front-end. I can't see any issues, I can't recreate it locally, and no other users are reporting this problem.
From here, I'd ask you send me a set of Super Admin credentials so we can investigate further what's going on. You can Private Message me by clicking the mail icon under my picture to the left.
It could be a problem with your SEF URLs (can you try turning them off, temporarily, to see if the redirect works?), a plugin (as mentioned above) or some other conflicting setting. I can't guarantee I'll be able to find it, because again, things look right to me.
The last thing I'd also ask is to configure the CB Login module to appear on some inner page of your site. With that, we can compare the output of our module vs CB Login to see if something screwy is going on.
I hope that helps get you started,
Alex