I had the same problem with 2.5 on a Mac (and with 2.4 and 2.5 on SGI). I
re-downloaded 2.5 several times and kept getting the same problem. I
finally downloaded it with Fetch instead of Netscape, and specified binary
on the Fetch download, and it came out fine. I then used Fetch to put the
..image and .changes file on my SGI (as binaries again) and my SGI version
is clean now too.

-Russell Swan