Hi John,
I've been out of XMPie for a while but I feel like there is a bad version of Gotham floating out there. I recommend making sure you are using a true Adobe OpenType version of the font. If it was converted but any software from Mac to Windows or PS to TrueType or whatever, trash it and get a good font to start with.
Then I recommend all production fonts be installed in Windows on the uProduce Server. That's going to work 99.999% of the time. THEN go ahead and load it up to the specific file as a font asset in uProduce.
InDesign Server will also look in a "fonts" folder if you keep it in the same root folder as your indesign document along with your Links folder if you have additional assets.
That should fix your issue. Also output a FAT pdf, no compression or anything no x1-A etc. Choose native InDesign output too, the other route uses Postscript intermediary steps that can mess things up too.
cheers,
Bob