Assign Custom Properties gives an empty page

I have bought today Custom Properties for Joomla 2.5 (I have used it earlier for Joomla 1.5).
Installed it without problems. I have checked that all files are writable.
Created a CP field and added a number of values to it.
When I press the option 'Assign Custom Properties' I get a complete blank page (without any error messages !! (this is the URL: www.lereninbedrijf.nl/administrator/inde...es&controller=assign )
I have added CP tags to a few pages and activated the CP Tags Cloud. The activated module is visible with the tags I have added. But when I click on a tag I get again a completely empty page.

Can you please help me find what is wrong in my installation or settings of the CP component.

Best regards,
Kees Gast

Hi,
the address you posted is from the site backend, hence we're not able to reach it without administrative rights.
Could you please create a temporary account and let us know the credential by email (info@...).
Also we don't see the tag cloud anywhere. Is it published only on a specific page?

Hi,
I have created an account for you and send the credentials by email.
Sorry, I had the tag cloud set to unpublished as it did not give meaningfull results.
The module is called 'Trefwoorden'.
Thnx