Crashing while playing on servers

I need some assistance with this. Whenever either my brother or I play on Garry’s Mod and try to join a server, we inexplicably crash. We play on the same computer, but on separate accounts. After the most recent crash, I used the Garry’s Mod Crash Dump Viewer to ascertain the situation. Unfortunately, I didn’t understand the problem. The closest I can gather to what is being said is that, besides the engine.dll issue, I seem to have memory issues.

Here is the crash dump in question.
http://dumps.garrysmod.com/?view=1891543296

If anyone could assist me on this, and as soon as possible, I would be most appreciative.

Engine.dll, one thing I can think, reinstall

Reinstall engine.dll, or reinstall Garry’s Mod?

Garrys Mod. You can also verify Garrys Mod in the library by right clicking on it and selecting properties, and then click on the Local Files.
A reinstall can do if verifying doesn’t work.