There is probably a missing link, for some reason:
$ ls -l /usr/lib/libssl.so
lrwxrwxrwx 1 root root 26 Dec 14 20:01 /usr/lib/libssl.so -> ../../lib/libssl.so.0.9.7a
So, what I suggest is:
1) find libssl.so.0. In my case:
$ whereis libssl.so.0
libssl.so: /lib/libssl.so.4 /usr/lib/libssl.so
$ ls -l /lib/libssl.so.*
-rwxr-xr-x 1 root root 213600 Oct 5 10:01 /lib/libssl.so.0.9.7a
lrwxrwxrwx 1 root root 16 Jan 16 2004 /lib/libssl.so.4 -> libssl.so.0.9.7a
2) Add a link for it, if it does not exist:
$ ln -s /lib/libssl.so.0.9.7a /usr/lib/libssl.so
$ ln -s /lib/libssl.so.0.9.7a /lib/libssl.so.4
3) re-run aMule and see what is the next error message. What? You thought it would be easy?

Your system has some brain damage, don't be surprised...
Cheers!