Gmod crashes when I connect to my friend's server

Me and my friend are playing together on his listen server. Sometimes when I or somebody else connects my friend’s Gmod crashes. Why does it happens? I have this same problem on my dedicated server, but there is an Engine error. Why is this happening? We are using about 15 addons including wire and phx3. Please help.
@edit: Ah i forgot: The error says "the memory could not be “read”… "

Can someone help?

What are your computer specs?

2 x 2.2 Ghz Core 2 Duo
GeForce 9400GT 1Gb
I dont think its caused by something with my computer beacause my friend has got this same problem.

Post all the addons

Here you are:

Way too many addons bro. Way too many. One or a few of them may be clashing with your friend’s server.

Also you shouldn’t have used the SVN folder directly. SVN creates extra file inside your addon to keep track of them, which slows down gmod. You should have downloaded the addons using SVN at another folder, and then export them back to the addon folder.

Remove all unecessary addons.

Also, try exporting. SVN Tutorial (which explains exporting)