The StationGlobals.ini file was overwritten by something. I use the following statement:
TS_PropertyGetValNumber (testData->seqContextCVI, ErrorInfo, "StationGlobals.PCN_Number", 0, &value);
I did not re-load TestStand and that statement worked before but when examining the contents of value, which equaled zero, I descovered that the StationGlobals.ini file was overwritten.