Hmm, that looks very similar (actually, the same) as I have.
I think somehow a software on your system has installed an incompatible msvcr90.dll which is causing that problem.
So here is what you could check:
1. If you do not already have this, download and install the Process Explorer (Process Explorer) from the Windows Sysinternals
2. Start a debug session with KDS so that arm-none-eabi-gdb.exe to reproduce that that "Runtime Error! R6084" dialog.
3. Start the Process Explorer.
4. Enable DLLs for the lower pane view:

5. Locate and select arm-none-eabi-gdb.exe:

6. In the lower pane you should have several MSVCR*.dll you need to check
7. The MSVCR90.dll should be loaded from WinSxS

The other I have is from syswow64:

What I think is that one of these DLL's on your system are loaded from somewhere else?
Especially check for the one which is not loaded from WinSxS, and make a note of that path.
8. Close the debugging session, so that the gdb is not running any more. Now check that Dll for the KDS executable:

I guess one or the other points to a different path/tool (e.g. from your virus scanner, or any other utility).
That way you hopefully can identify the offending utility.
I guess that this offending utility has added the path to itself into your PATH system variable.
You could try if moving that offending utility path to the end of the PATH variable.
I hope this helps,
Erich