Hiya With http://c93.keble.ox.ac.uk/~ian/igl-0.0.8.tar.gz compiled with make nhc I get $ ./Project -d +RTS -H4M -RTS < Demo.lhs > Demo.tex hPutStr: internal error, not a cons-list! hPutStr: got CONSTRW src=0x809b384 size=1 hPutStr: char='I' $ Thanks Ian