When searching for a string in AMOS 2.0-2.6, hitting the Filtering button returns an empty view page in Waterfox and Chrome.
It is very likely that the PHP max execution time limit ran out while AMOS was still performing the search. I know there should be some better output in that case, I just haven't managed yet to implement it, sorry.
Try to make the search criteria more restrictive, e.g. search in a limited set of components, versions etc. That usually helps.