Please, follow ALL steps EXACTLY. One of most common errors when generating UNL files with NOTEPAD is file created with name GMAPSUPP.UNL.TXT
You can not see .TXT at end of file name because Windows is hiding it by default if this option is not disabled.
Try to use modified keygen from my post (map ID is 2048 and old keygen is generating WRONG key for this map ID) and generate GMAPSUPP.UNL file with tool from P.S. of post which is generating file name correctly and with correct name (DO NOT use NOTEPAD).
Click with mouse on underlined words "here" and "this" in my previous post and You will get links to files You need.