SharePoint form-based authentication problem with itemDeleting event?

Question

Hi!

I have a SharePoint site (I'm the farm administrator with full control over the farm and site) and I used Windows authentication. I had a event receiver feature installed which manage add/update/delete for my lists to have custom behavior. Everything worked ok on Windows Authentication.

But... now I am using form-based authentication (the same, I'm the site administrator with full control), but my feature works fine only with add/update events.... delete doesn't work any more, and it's the same code (damn it) as it was on windows authentication.

Where am I doing wrong? why delete items don't work any more?

Thanks in advance