cabal: : openFile: does not exist (No such file or directory)

Hello, I'm on Ubuntu 8.10. I installed ghc 6.10.4 (from binary package: ghc-6.10.4-i386-unknown-linux-n.tar.bz2). I installed haskell-platform-2009.2.0.1 (from source package: haskell-platform-2009.2.0.1.tar.gz). It contains cabal-install-0.6.2. Then when I run "cabal update", I get the following error: cabal: : openFile: does not exist (No such file or directory) Any ideas? Thanks, Tony