Failed to load interface for `Hat.PreludeBasic'

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

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Any idea what the problem could be?
CC me in the reply please, I don't subscribe.