This indicates that the temp file may be full.
Right click Windows start button> select Run
Type in %temp% and press enter or select Ok
This will open the temp file
Delete all files within the folder by pressing Ctrl + A to select all files, then press Ctrl + delete to delete all files within folder.
Once all files have been deleted from temp folder
Proceed with a reboot of computer.
Once the computer is back up and running login to The Uniform Solution and try to run a report in Preview mode or try to save as a PDF
Your issue should be resolved