Error internal exception io.netty.handler.timeout.readtimeoutexception displayed on my client?

While minecraft was in about 1.4, i shutdown my server. my minecraft stopped working properly but the server ran fine. since i could not monitor it, i closed it. now my minecraft is working again so i decided to see if i could start my serer back up. Everything seemed to work fine but after about playing for 5 minutes, i get kicked and my client says internal exception io.netty.handler.timeout.readtimeoutexception. When i lag out like this, the console says that the server is running behind anywhere from 20000 to 30000ms. Then it says that i left the game just as if i clicked the disconnect button but i see that error on my client. the server runs 4gb RAM.
My computer specs are: 8gb Ram, AMD quad core processor, AMD radeon 66550D qraphics, windows 7 x64.
I have tried the solutions that are listed online like more ram, restart your internet, restart the server, reinstall minecraft, ect with no luck.

 

Most likely your end like the connection or your server could of been over loading