I know this is an old question but what about printing the excel-based pattern? Then scan that using a flatbed scanner, save it as a .JPG with 100% quality. Now you can import that into PC Stitch to convert it to a .PAT file. Once saved as a .PAT file you can export to .PDF using Microsoft's .PDF printer.
Looking back, the problem may have been fixed - by either PCStitch or Microsoft. It looks like the problem existed for PCStitch 9 and 10 but I've not seen the complaint since 11 came out. Maybe that's because those who had the problem had used the "fix" of using another PDF creator.
When Microsoft's PDF Printer was selected as the printer, it would lock up ALL printing and, I think, the product had to be reinstalled to take that off the default printer to get things back running. Otherwise, selecting printing did nothing. That's what the reports were. I can't say. I've never used that printer.
I used to use PrimoPDF but got mad when I tried to install it on a Win 8.1 laptop and it kept trying to add MORE garbage programs as I was trying to remove them! I removed it anywhere I had it. By that time most PDF clones had their own printers. I've been very happy with the one that comes with Foxit. I prefer NOT to use Adobe because it has more overhead than does Foxit.