A problem with Paint.Net SFX Setup

Hi,
I have updated my Windows 8 to Windows 8.1 and I have this error when I want to open some programs. The first error is this with Paint.Net. I never experienced this error before and I don’t know what happened. Does anyone can help me to fix this ? Why I have this kind of errors? It might be because of the update? Thank you!

Error opening file for writing:
C:UsersMartinAppDataLocalTempPdnSetupSetupshim.exe
Click Abort to stop the installation,
Retry to try again, or
lgnore to skip this file.
