I faced such a problem when I changed files after unzipping with UniExtract2, and then I don't know how to put everything back together. I tried to create an executable SFX-archive using WinRAR built-in function. But then I found out that it creates an installation file which I don't need, but I need an .exe executable file. If what I edited, I was editing The Elder Scrolls IV: Oblivion launcher.
I guess you found the answer yourself, but for anyone else looking at this issue: repacking is not supported ans i don't plan on adding this functionality. See the FAQ for more information.
I faced such a problem when I changed files after unzipping with UniExtract2, and then I don't know how to put everything back together. I tried to create an executable SFX-archive using WinRAR built-in function. But then I found out that it creates an installation file which I don't need, but I need an .exe executable file. If what I edited, I was editing The Elder Scrolls IV: Oblivion launcher.