O.K. So I play on a Windows 7 and I have been trying to install TooManyItems like 10 times and I can't get it right. I use a zip and i went into my minecraft.jar in bins and deleted META.inf and moved all the files in TooManyItems.jar to the minecraft.jar. Then i went to my worlds and went to inventory and pressed "O", but it didn't work. HELP???? ( I even tried it in a newly created world)
Did you follow the installation instructions thoroughly? I mean, did you mean TooManyItems.zip/rar, because I can't recall downloading it as a jar. I'd assume it's a typo, but if it's not then that version may be relying on an API.