How do I merge two vobsub (idx/sub) subtitle files into one vobsub file

[gilgamesh-au]

I have a movie I'm trying to rip that was split across two discs. I can easily join the video and audio components but I'm having trouble with the sub-titles.
I have ripped the subs from each disc into vobsub idx/sub format and I have edited time time code on the second set to offset it by the length of the first part of the video but I can't find a way to merge the two vobsub files into one vobsub.

I have seen suggestions of using the Vobsub utility which I have installed, but the install seemed to miss the vobsub.dll file needed to do the merge.
I have also seen a suggestion of using Subtitle-Creator. I installed versions 2.2 and 2.3rc1 but was unable to get the files to merge.

I know that I could convert the vobsub to srt using OCR and merge the resulting text files but I want to avoid that if possible (OCR is unreliable in my opinion)

I am doing this in Window 8.1 64bit. I have VMWare so if a suggested tool requires a different version of windows I can easily accommodate it.

[manono]

I can't quite understand if you tried it already, and if you did why it didn't work. But you should use VobSub Joiner, a utility that comes included in the VobSub package.

[netmask56]

What is the final format that you require after merging?

Try vobsub joiner, it apparently appends the second one after the first if that is what you want? https://www.videohelp.com/software/VobSub

[gilgamesh-au]

I have tried VobSub joiner but it complains about a missing file vobsub.dll. It seems that the install does not put it into the C:\Windows\System32 directory and a search of my C: drive doesn't show the file at all. I have uninstalled and reinstalled multiple times but can't get the file.
The install for VobSub has plugins for AVISynth, AVIUtil, and VirtualDub. None of these were originally on my PC but I installed them and reinstalled VobSub in case they were necessary to get the dll but the result was still a missing file.

I would prefer to keep the final output as VobSub idx/sub format the same as the input files.

[manono]

Mine's in my System32 folder. Here's a copy if you like. But shouldn't yours be in the SysWOW folder, since yours is 64 bit?

[gilgamesh-au]

Sorry for the delay in getting back.
Even though my search on my entire C: drive for vobsub.dll didn't show anything it was in the SysWOW64 directory after all.
But I have found the cause of my issue.
I was installing the standard 32 bit version of VobSub on my 64bit system. The shortcuts that the install process created had a target of "C:\Windows\System32\rundll32.exe vobsub.dll,Joiner". So while the install process put vobsub.dll in SysWOW64 it didn't change the links it created.
After I manually changed the links to the correct directory it started working.
Thanks for your help as it was your suggestions that guided me to a resolution of the problem.