This was a known bug in the that version of insmod. There
was a patch posted here and on axp-list you could search for
in the archives.
You might also try modutils 2.1.23. You'd need to pull down
a new copy of linux/include/asm-alpha/unistd.h from 2.1.23
as well to get it to build, but other than that it should work.
r~