NO NEED TO MAKE ME A SPECIAL FIX GOOD SIR! searched other forums with GOTY version and found a guide using your normal fix! thanks for the patch by the way!
for anyone having trouble with the GOTY edition of batman (mine is US version don't know if their is a EUR version):
if zombiekillah patch was installed but won't run DLC (harley quinn).
1. delete game date
2. install zombiekillah patch
3. nstall Batman Arkham City EUR & US [BLES00926 & BLUS30538] DLC Fix
4. reinstall zombiekillah patch again.
if zombiekillah patch is not yet installed just skip step 1.
hope this helps. :D