Advice on avoiding corrupt .2h files?

[Arralen]

Zip them. Files with 'unknown' file extension sometimes get mangled by mail servers during 8<->7 bit conversion.

If you're using dial-up connection, check for error correction settings on your modem.

[Agrajag]

Just in case, its a good idea to make sure your hard drive is okay.
My old hard disk was worn out, but still working, but every now and then a file would become corrupt (especially newly created files, like downloaded files or copy+pasted files).

I think that Arralen's solution is more likely the appropriate one, though.

[Daynarr]

Anti virus, anti spam checks (updated to most recent version)are also smart idea. Viruses can sometimes corrupt files.

And yes, Arralen is most likely correct in this one.