Probably a problem with the php exception handler, in particular in getting a second exception after trying to handle an exception. See the PHP manual for set_exception_handler(), in particular the user contributed notes.
Comment on Re: Passing PHP objs to PHP instantiate with PHP::Interpreter
Thanks, but I think the root of the problem is that when I pas an object to a call PHP::Interpreter isn't turning it back into a PHP object properly, I did a little test and I seem to get a string with the object name instead of an object.