The FVU file (File Validation Utility) or the PDF converter utilities are basically Java-based utilities provided by the Traces (TDS) department. The utility of the department would respond only if there is required JAVA installed on the system.
The minimum required version of JAVA should be 8 or above. (Check the version from Control Panel >> Program and Feature >> to get help in knowing the installed JAVA on the system)
If there are multiple JAVA's installed on the system, then the command line "Java -Version" will help to know the java running on the system.
Below are the few possible JAVA Errors--
FVU Generation error --> File validation utility not found
Reason: Error occurs when the FVU files (.jar files) are missing at the root location of the software.
Default location “C:\Program Files (x86)\K.D.K. Software\Spectrum\Zen TDS\e-TDStcsfvu”
Solution : Please update the software to the latest version on both the SERVER system and LAN system.
Additionally, clicking the "Yes" button will automatically download the file.