This appears to be a Hat installation problem. Running the command "hmake -v -hat Test" yields the results: ------------------------------------------------------------------------------------ hat-trans DoublyLinked.hs Wrote Hat/DoublyLinked.hs /usr/bin/haskell-compiler -v -c -package hat -o Hat/DoublyLinked.o Hat/Doub lyLinked.hs Glasgow Haskell Compiler, Version 6.4.1, for Haskell 98, compiled by GHC version 6.4.1 Using package config file: /usr/lib/ghc-6.4.1/package.conf Hsc static flags: -static -funregisterised *** Checking old interface for Hat.DoublyLinked: *** Parser: *** Renamer/typechecker: Hat/DoublyLinked.hs:11:0: Failed to load interface for `Hat.PreludeBasic': Could not find module `Hat.PreludeBasic': locations searched: Hat/PreludeBasic.hi Hat/PreludeBasic.hi-boot *** Deleting temp files Deleting: /tmp/ghc7184.hc Warning: deleting non-existent /tmp/ghc7184.hc ------------------------------------------------------------------------------------- I have explicitly enabled hat via ghc-pkg -l lists "hat" not in parenthesis, so I think the package is enabled. ---------------------------------------------------------------- When apt-getting hat for ubuntu 6.06, note the troubling output of the package manager "ghc-pkg: cannot find package hat" - this was before the hat package was enabled -- could this be the problem? If so, should I more properly ask the package maintainers about this? Setting up hmake (3.10-1.1) ... Setting up hat (2.04-0ubuntu2) ... Setting up hat-ghc6 (2.04-0ubuntu2) ... ghc-pkg: cannot find package hat Reading package info from stdin ... done. Saving old package config file... done. Writing new package config file... done. ------------------------------------------------------------------------------------ Possibly related: "[Hat] hat installation problem" http://www.haskell.org/pipermail/hat/2006-February/000255.html ------------------------------------------------------------------------------------- Any idea what the problem could be? CC me in the reply please, I don't subscribe.