Alright, I got some time for this now. I've created a zip file that contains the version of Lemmix on Erik's website, plus the data files for the various DOS Lemmings games (Lemmings, ONML, the 4 Xmas packs, and CustLemm). Note that data files for non-DOS games like WinLemm and Lemmini are not included, because I don't have those files on the computer at the moment.
SPECIAL INSTRUCTIONS, READ NOW AND READ THIS FIRST, BEFORE PROCEEDING!When you extract files from the zip file, you need to specify
exactly the folder to extract it to, otherwise Lemmix will not find the various files it needs. Specifically, the zip file is set up to be extracted exactly into a folder named "Lemmix" (minus surrounding quotation marks) right under your C drive. If you use Windows to unzip, this means when it asks for the folder to extract files to, you type "c:\Lemmix" (minus the surrounding quotation marks). Proceed similarly with other unzip programs you may use.
You cannot move the files from c:\Lemmix folder to anywhere else. If you do, then you need to go into the "LemmixStyles.ini" file in a text editor (eg. Notepad), and replace all instances of "c:\Lemmix" with the path to whatever new folder you moved the files into. Of course, if you are able to do that, then you probably didn't have trouble setting up Lemmix before, so the fact that you need this means you should absolutely avoid deviating from my instructions.
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Anyway, now that we got that out of the way, here's the link where you can download:
http://www.fileden.com/files/2010/7/15/2915232/Lemmix.zipLet me know if you have any issues.