Ubuntu’s version of tar (1.22-1) includes a regression, which causes the build to fail with the following or a similar error:
NOTE: package libtool-cross-1.5.10-r4: task do_unpack: started
gzip: stdout: Broken pipe
tar: Child returned status 1
tar: Exiting with failure status due to previous errors
This problem has already been corrected in versions 1.22-1.1 and later, which however are currently not part of Ubuntu 9.10.
You can find installable builds of newer versions for various architectures on Launchpad.