I cannot search for a strint, maybe, the question mark is guilty:
Yeah, that is expected result of a search that takes all available memory. PHP processing halts with the fatal error. Unfortunately, AMOS can't detect such case well in advance yet. Instead of a nice error message, it just leads to a white screen of dead or an error like the one reported.
What helps in these situations is to make the area to search smaller. Eg selecting just one version instead of three, or selecting just a subset of components instead of all (or all standards) etc. Also, searching by string identifier and searching help texts only help the memory consumption significantly as these filters are applied by the SQL server itself. All other filtering happens in PHP.