The best way is to ask Steam Support.
You got an error writing communication packets. Make use of application below to fix mysql errors
It can be file or registry corrupt - you can fix it with Rundll Error Fix Wizard - this one helped me (google it).It can also be a virus - if so scan your PC with antivirus with latest updates.
autoIt error how can i fix this problem
Try to run "SFC /SCANNOW" and fix the computer as it will help!
How to fix the LaunchAnywhere error depends on the specific problem you're countering. If it says you're missing files, you can try uninstalling and then re-installing the application.
How to Fix file integrity violated Error
How to fix the error on FMC
How do you fix error code 489 on my android phone
How do I fix error code 1712 for Mac?
Can you tell me how to fix error Out of memory at line 23?
it can be different from error to error
First you need to port forward. (http://portforward.com) Go there fix that then start up Gmod choose "Create Multi player" or something like that. Now invite your freinds and have fun!