Latest set of problems. I've tried using the i386 build of GHC 6.10.4 to build the x86_64 version in the manner that I described in an earlier post. I'm not getting any segfaults now, but instead it says the following during make: /Users/bjs/Desktop/GHC_Build/ghc-6.10.4/libraries/cabal-bin /usr/bin/ ghc /Users/bjs/Desktop/GHC_Build/ghc-6.10.4/libraries/ bootstrapping.conf 1.6.0.3 build --distpref dist-install --ghc- option=-H32m --ghc-option=-O --ghc-option=-I/sw/include --ghc-option=- L/sw/lib --ghc-option=-Wall Preprocessing executables for installPackage-1.0... Building installPackage-1.0... [1 of 1] Compiling Main ( installPackage.hs, dist-install/ build/installPackage/installPackage-tmp/Main.o ) /var/folders/IZ/IZ09PkvEHBmw7qmXrvZvFE+++TI/-Tmp-/ghc38027_0/ ghc38027_0.s:3616:0: Bignum number illegal. Absolute 0 assumed. /var/folders/IZ/IZ09PkvEHBmw7qmXrvZvFE+++TI/-Tmp-/ghc38027_0/ ghc38027_0.s:3677:0: Bignum number illegal. Absolute 0 assumed. /var/folders/IZ/IZ09PkvEHBmw7qmXrvZvFE+++TI/-Tmp-/ghc38027_0/ ghc38027_0.s:3709:0: Bignum number illegal. Absolute 0 assumed. etc... Looking in the assembler file, I get stuff like: Lc4a1: jmp *-16(%r13) .long _s3j4_info - _s3j4_info_dsp .text .align 3 _s3lv_info_dsp: .quad _Main_a1_srt-(_s3lv_info)+72 .quad 3 .quad 37590000000000174587920 _s3lv_info: Lc4bb: leaq -16(%rbp),%rax cmpq %r14,%rax (That bignum is at line 3616.) Any ideas what might be causing this? Cheers, Barney.