Starting with Joomla 2.5.8, you might encounter a database problem which refers to assets table when you browse some of the jomSocial pages.
Please note, that this is not jomSocial specific error as we dont use that table at all.
Joomla! already described why this happens, and even have its own documentation article covering the fix for it
Also, Joomla Forums have the answer for the issue.