Random rpm script failures

[Ivan Gyurdiev <ivg2 cornell edu>]

Rawhide...I've been seeing random script failures like this: exit code 255.

Preparing...                ########################################### 
[100%]
  1:libcap                 ########################################### 
[ 17%]
error: %post(libcap-1.10-23.i386) scriptlet failed, exit status 255
  2:libgtk-java            ########################################### 
[ 33%]
error: %post(libgtk-java-2.8.1-1.i386) scriptlet failed, exit status 255
  3:libcap-devel           ########################################### 
[ 50%]
  4:libgtk-java-devel      ########################################### 
[ 67%]
  5:tar                    ########################################### 
[ 83%]
error: %post(tar-1.15.1-11.i386) scriptlet failed, exit status 255
  6:tftp-server            ########################################### 
[100%]
error: %post(tftp-server-0.41-1.i386) scriptlet failed, exit status 255
error: %postun(libcap-1.10-22.i386) scriptlet failed, exit status 255
error: %postun(libgtk-java-2.8.0-7.i386) scriptlet failed, exit status 255

All kinds of scripts will fail, including preun, postun, pre, post, and 
trigger. The exit status is always 255. Some of those scripts are really 
simple:

[root cobra packages]# rpm -q libcap --scripts
postinstall program: /sbin/ldconfig
postuninstall program: /sbin/ldconfig

[root cobra packages]# rpm -q tar --scripts
postinstall scriptlet (using /bin/sh):
/sbin/install-info /usr/share/info/tar.info.gz /usr/share/info/dir
preuninstall scriptlet (using /bin/sh):
if [ $1 = 0 ]; then
  /sbin/install-info --delete /usr/share/info/tar.info.gz 
/usr/share/info/dir
fi

This causes chaos in my rpm databases, which I must later fix manually - 
it's really driving me crazy. I hadn't reported it so far, since I 
assumed it's a known problem, and will be fixed, but now I'm starting to 
suspect that only my system is broken...  ideas?