"failed to serialize server result" when install

Hello all,

i m a newbie, so please excuse if my question looks noob.

i m installing kaltura on my joomla hosted in limewebs free hosting.

after i install the module, i go to the configuration / registration page, no matter i use a fresh registration or exist id, it always prompts me the same error msg:

can anyone give me some tips on this?

thanks.