Unity3d 5.1.0f3 bug?

Hello everyone,
I just uninstalled Unity3D and installed it in another disk.
When I first launched it, this error started to come up.
No scripts are being debugged nor the game’s being played.
Help please,
PeterAS17

I have no idea why, but I recommend you get Patch 5.0.3p2.
Unity 5.1.0f3 has a UNet bug where it spams some error messages. I am downloading Patch 5.0.3p2 and it might work for you too.

http://unity3d.com/unity/qa/patch-releases