Getting the error The requested File is not a valid font file I've done some research about registry changes where you put SessionImageSize with DEC of 20 but that was for XP 64bit. I can't seem to find anything about installing fonts for Windows 7. I've tried with TTF and OTF
Also, if the font files are contained in a ZIP (which is how most Adobe OTF fonts are packaged) you can't just drag-n-drop them to the Control Panel > Fonts folder, even though Windows 7 treats ZIP files like a folder.
First you need to copy them to a standard folder to uncompress them, and then you can drag and drop the uncompressed *.OTF files to the Control Panel > Fonts folder.
I'm having the same issue installing OTF fonts on Windows7 64bit - moved fonts out of the zipped folder, dragged the fonts into control panel/ fonts and still get 'invalid font' error. this thread and OP's problem hasn't been solved as far as i'm concerned!