I checked out your ILDA file. Format 3 is kind of obsolete but I do support it in Spaghetti. But, when I get your Format 3 header I get an error when reading the data length right after the 4 format bytes. The ILDA standard says the data length should be an unsigned 32 bit value but when I read those from your file I get huge numbers which indicates that your format is not per the standard. The next four bytes that are used to indicate number of points also yield a crazy huge value. I'll check into it some more later to see what you are doing.
I can read in your Format 2 color tables just fine.
Spaghetti uses Format 4 and 5 for output since it allows 24bit colors without using color tables. It's a much nice format in my opinion.