Ghostsctipt Error: /undefined in INVOICE

When attempting to print invoices from Attache, I get the following error in the log…

12:07:56.6927 [Error]
pdfforge.PDFCreator.Core.Jobs.GhostscriptJob.RunJobWork: Ghostscript
execution failed: Error: /undefined in INVOICE
Operand stack:

Execution stack:
%interp_exit   .runexec2   --nostringval--   --nostringval--  
–nostringval--   2   %stopped_push   --nostringval--  
–nostringval--   --nostringval--   false   1   %stopped_push   1932  
1   3   %oparray_pop   1931   1   3   %oparray_pop   1915   1   3  
%oparray_pop   1803   1   3   %oparray_pop   --nostringval--  
%errorexec_pop   .runexec2   --nostringval--   --nostringval--  
–nostringval--   2   %stopped_push   --nostringval–
Dictionary stack:
   --dict:1207/1684(ro)(G)--   --dict:0/20(G)--   --dict:85/200(L)–
Current allocation mode is local
Current file position is 24

2016-01-15 12:07:56.8487 [Error] pdfforge.PDFCreator.Core.Jobs.AbstractJob.RunJob: Executing Ghostscript failed

Attache reports print to pdf with no problem, it seems to be invoices only at the moment that are giving me an issue… Attache have a document delivery service they’re trying to sell to me - maybe they have blocked pdf printing to make it impossible for me to do my own electronic documents to send to customers?