The error is caused by a font compatibility issue.  A recent Windows 11 update introduced Times New Roman version 7.05, which conflicts with the software’s Crystal Report engine, failing PDF exports. 
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Hy-Tek’s development team is working to update report fonts in TFMM & TFTM to resolve this issue.  A practical workaround for now is to:
  1. Click the Print Report icon (next to the Export Report icon).  
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  1. Select "Microsoft Print to PDF" as the printer.  
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  1. Print to save the file as a PDF.