running OS on bochs returned error

I'm working on an OS programming project called pintos. It is run on bochs following the command pintos run nameOfProcess

And here's the error message I get

Writing command line to /tmp/eKW3NMXoGT.dsk...
 squish-pty bochs -q
 ========================================================================
                      Bochs x86 Emulator 2.5.1.svn
              Built from SVN snapshot, after release 2.5.1
                   Compiled on Apr  6 2012 at 19:37:19
 ========================================================================
 00000000000i[     ] reading configuration from bochsrc.txt
 00000000000i[     ] installing x module as the Bochs GUI
 00000000000i[     ] using log file bochsout.txt
 Next at t=0
 Writing command line to /tmp/eKW3NMXoGT.dsk...
 squish-pty bochs -q
 ========================================================================
                      Bochs x86 Emulator 2.5.1.svn
              Built from SVN snapshot, after release 2.5.1
                   Compiled on Apr  6 2012 at 19:37:19
 ========================================================================
 00000000000i[     ] reading configuration from bochsrc.txt
 00000000000i[     ] installing x module as the Bochs GUI
 00000000000i[     ] using log file bochsout.txt
 Next at t=0
 (0) [0x00000000fffffff0] f000:fff0 (unk. ctxt): (invalid)                 ; ffff
 <bochs:1> fgets() returned ERROR.
 debugger interrupt request was 0
 (0).[0] [0x00000000fffffff0] f000:fff0 (unk. ctxt): (invalid)                 ; ffff
 (0) [0x00000000fffffff0] f000:fff0 (unk. ctxt): (invalid)                 ; ffff
 <bochs:1> fgets() returned ERROR.
 debugger interrupt request was 0
 (0).[0] [0x00000000fffffff0] f000:fff0 (unk. ctxt): (invalid)                 ; ffff
 

Also my bochsrc.txt

romimage: file=$BXSHARE/BIOS-bochs-latest, address=0xe0000  
 vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest
 boot: disk
 cpu: ips=1000000
 megs: 4
 log: bochsout.txt
 panic: action=fatal
 clock: sync=none, time0=0
 ata0-master: type=disk, path=/tmp/eKW3NMXoGT.dsk, mode=flat, cylinders=1, heads=16, spt=63, translation=none
 com1: enabled=1, mode=term, dev=/dev/stdout
 

Bochs was built from source with extra configurations on my Ubuntu 11.04

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