Black screen, cursor

[jorge]

The program worked fine the first run, but then it stopped working. Now all I get is a black screen with a low-res cursor that crashes X.

ldd penumbra.bin gives:
............
libGLU.so.1 => /usr/lib/libGLU.so.1 (0xb7d8f000)
libCg.so => not found
libCgGL.so => not found
libopenal.so.1 => not found
libalut.so.0 => not found
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xb7c9f000)
.................
, while lib/ contains all four missing files. Yes, Urkl, everything is up to date. Where can I tell penumbra to look in that path?
Thanks.