I haven't used Aquisition in a while. I think they have their own forum. Sounds to me like all you're receiving in search results are spam then. Be aware of these spam file sizes Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see). You could check the how to eliminate porn link (near bottom of post #2) which links to other spam words, add those to your keyword filter. This will no doubt help somewhat.

There is also an ip spam blocker list (Hostiles List) which helps to block out some spam, however this might not work with Aquisition, which is an adapted version of the LimeWire code.