make trouble (Score 1)

i'm have a bit of trouble compiling the source. i'm pretty new to linux and i'm running Suse 9.1. this is the message i get when i run 'make'

cc -pipe -Wall -D_LINUX -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -O4 -D_OPENSSL_MD4 -g3 -ggdb -c -o common.o common.c
common.c:32:25: openssl/md4.h: No such file or directory
common.c: In function `NtPasswordHash':
common.c:129: warning: implicit declaration of function `MD4'
make: *** [common.o] Error 1

any help is appreciated! cheers