hs-plugins runtime error with GHC 6.6: index out of range

After upgrading from GHC 6.4.2 to GHC 6.6 and rebuilding hs-plugins package, I noticed that hs-plugins does not work anymore. When I try to load a plugin, I get an "Index out of range" error. For example, when I compile the hs-plugins\testsuite\make\simple example and run the executable, the error message is a.out: Ix{Int}.index: Index (65536) out of range ((0,11)) Other tests give similar results; the values of the index and the range vary. Does anybody know what is wrong here? I use hs-plugins-1.0-rc0 and GHC 6.6 on Windows (hs-plugins worked fine with GHC 6.4.2). Cheers, Cyril