Hmm... This should not be happening unless .NET Framework 4 was installed after most recent UWS installation, because UWS does grant appropriate permissions to "Temporary ASP.NET Files" folder. If .NET Framework 4 was installed after UWS installation, you could run UWS "Repair Server Configuration" utility and try again.
Please take a look at "C:\Program Files\UltiDev\Web Server\UWS.Installer.log.txt" file and see whether there were any errors around "Creating temporary ASP.NET folders..." section. Please also consider sending us the file above for analysis. You may put the file into password-protected ZIP and attach it to your response, while sending us the password over the PM.
Best regards,
UltiDev Team.
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