It's very rare case and only happens when BB_NUMBER_THREADS is a high number and tow patching processes happen to generate the same temp file name(e.g. /tmp/po5gPxpP in the following failure) and are trying to create or open it at the same time:

+NOTE: Applying patch 'module_build_man_extensions.diff' (../layers/oe-core/meta/recipes-devtools/perl/perl-5.14.2/debian/module_build_man_extensions.diff)
+ERROR: Command Error: exit status: 1 Output:
+Applying patch module_build_man_extensions.diff
+patching file cpan/Module-Build/lib/Module/Build/Base.pm
+patch: **** Can't reopen file /tmp/po5gPxpP : No such file or directory
+Patch module_build_man_extensions.diff does not apply (enforce with -f)
+ERROR: Command Error: exit status: 1 Output:
+Applying patch bash42-009
+patch: **** Can't create file /tmp/po5gPxpP : File exists
+Patch bash42-009 does not apply (enforce with -f)
+ERROR: Function failed: patch_do_patch
+ERROR: Task 626 (/ala-blade291/nxadm/nx/ala-blade29.1/builds-2012-08-31-113750/qemux86_std_bd/layers/oe-core/meta/recipes-devtools/perl/perl_5.14.2.bb, do_patch) failed with exit code '1'
+ERROR: Logfile of failure stored in: /ala-blade291/nxadm/nx/ala-blade29.1/builds-2012-08-31-113750/qemux86_std_bd/bitbake_build/tmp/work/i686-wrs-linux/bash-4.2-r4/temp/do_patch/log.do_patch.

It is known bug for patch(http://savannah.gnu.org/bugs/?29944) and should be fixed in the version later than the following commit in upstram patch:
-----------------------------------------------
commit fdafb60cc0d920fe3f31965013235fbd7fc9d592
Author: Andreas Gruenbacher <agruen@suse.de>
Date:   Thu Sep 16 13:25:32 2010 +0200

    Stop using mktemp() for TMPOUTNAME

I can't find out which version it was from that point, but at least the latest 2.6.1 alpha versions in ftp://alpha.gnu.org/gnu/patch/ should fix this.

And since there is no patch-native and we use the patch on the host instead, the issue would happen on most host without the above new patch version, so I think it would be a solution for this to uprev patch to the latest version and adding the patch-native.