I have seen situations where malicious software knows that you are trying to run Task Manager and will not let taskmgr.exe exist as a running process. The malicious software knows you might use Task Manager to try to find and remove it so it will not
let it run.
I have never seen your error - usually TM just will not start and there is no message, but to "fool" it here is what I usually do:
You can fool the malicious software (then fix it).
Assuming your Windows is installed on your C drive, using Windows Explorer, navigate to the c:\windows\system32 folder and locate taskmgr.exe.
Copy the taskmgr.exe file and rename the copy something that the malicious software will not recognize. I like to call the copy:
c:\windows\system32*jose.exe*
Double click jose.exe and see if the Windows Task Manager window will open now.
The problem is the malicious software will not let the taskmgr.exe be a running process, but it does not know about jose.exe as a running process so you just outsmart it (I have a feeling that it will know about jose.exe someday though).
That will not "fix" your Task Manager but at least you will know if the Task Manger mechanism works or not (taskmgr.exe still will not launch as it should). If you are trying to remove some malicious software and need to use Task Manager, you can just launch
(double click) jose.exe instead, but your system will still be infected.