My config: runghc 7.4.1 3.2.0-61-generic #93-Ubuntu I installed Haskell using Ubuntu's "apt-get install" ======================================================== Please see results below ... (should I instead install Haskell from haskell.org??) vasili@vasili-VirtualBox:~/biolib$ cabal configure Resolving dependencies... Configuring bio-0.5.2... Warning: This package indirectly depends on multiple versions of the same package. This is highly likely to cause a compile failure. package text-1.2.0.0 requires bytestring-0.10.4.0 package tagsoup-0.13.3 requires bytestring-0.10.4.0 package parsec-3.1.7 requires bytestring-0.10.4.0 package bio-0.5.2 requires bytestring-0.10.4.0 package binary-0.4.5 requires bytestring-0.10.4.0 package unix-2.5.1.0 requires bytestring-0.9.2.1 vasili@vasili-VirtualBox:~/biolib$