I have spent some time and, when I unregistered (with ghc-pkg unregister) all dependencies (even indirect dependencies) I have installed since I have the Haskell Platform, then the &quot;cabal install ftphs&quot; worked.<br>
<br>Now I feel I understand the problem, but still seems annoying.<br><br>Thanks for the pointer, Jeff. I didn&#39;t know the reason of your question, but then I saw dependencies of network and thought: &quot;eureka!&quot;.<br>