Created attachment 9946 [details]
test file showing the error

When trying to convert the attached PDF I get different errors depending on the Ghostscript version I use.
Even though v9.07 processes the file despite the error the output file lacks most of the original page content.

I have a couple of those files which are not working. It seems that the dotted lines are an issue. When changed to solid lines everything works.


Also the error changed from 
"Pattern stream has unbalanced q/Q operators" in v9.04
to
"Form stream has unbalanced q/Q operators" in v9.07


No Preflight-check in Adobe Acrobat 9 shows any errors. Especially the "unbalanced q/Q" check passed with flying colors.


===========================================

v9.04: 
   **** Error reading a content stream. The page may be incomplete.
   **** Warning: Pattern stream has unbalanced q/Q operators (too many q's)

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****

   **** File has unbalanced q/Q operators (too many Q's) ****
Error: /rangecheck in --.discardtransparencygroup--
Operand stack:
   --dict:9/18(L)--   1   10   3   --nostringval--
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   false   1   %stopped_push   1926   1   3   %oparray_pop   1925   1   3   %oparray_pop   1909   1   3   %oparray_pop   1803   1   3   %oparray_pop   --nostringval--   %errorexec_pop   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   --nostringval--   --nostringval--
Dictionary stack:
   --dict:1174/1684(ro)(G)--   --dict:1/20(G)--   --dict:86/200(L)--   --dict:108/127(ro)(G)--   --dict:291/300(ro)(G)--   --dict:23/30(L)--   --dict:6/8(L)--   --dict:25/40(L)--
Current allocation mode is local
Last OS error: No such file or directory
pdf_page failed


===========================================

v9.05: 
endless error loop

===========================================

v9.06: 
endless error loop

===========================================

v9.07: 
**** Error reading a content stream. The page may be incomplete.
**** Warning: Form stream has unbalanced q/Q operators (too many q's)
**** File did not complete the page properly and may be damaged.