Stmgr is a part of Windows System Restore which is used to take your computer back to a point in time called a restore point when the computer was working correctly. This error could have been caused by a Windows update that did not install correctly, or some sort of spyware or virus that is trying to affect your stmgr file to affect your System Restore or even just some corruption in the file itself.
You can also check your startup items using MSconfig to see if there is anything that references stmgr listed under the startup items tab and uncheck it then try rebooting.
The Kernel32.dll file handles memory management, input/output operations, and interrupts. There are many types of Kernel32.dll errors and they can even be caused by faulty RAM.