Analyzing BSOD dump file from Windows 2008 R2 SP1
Solution 1:
This looks like the issue described in the following KB article:
https://support.microsoft.com/en-us/kb/2359223
"0x0000003B" Stop error occurs in Windows Server 2008 R2 and in Windows 7 when an application or a service performs a GUI-related operation
The reason I think it is the issue described in the hotfix is because it specifically calls out the win32k.sys driver. Also, the CSRSS.exe process which also shows up in the dump is used in inter-process communication between user-mode GUI operations and the kernel which is also indicative of the issue described in the hotfix (reference: https://en.wikipedia.org/wiki/Client/Server_Runtime_Subsystem).
I would recommend applying the hotfix in the KB article and monitoring to see if the stop errors continue.