Well this one stumped me for a little bit today:
Not much information on Metalink or Google. In the past one issue that would crop up every now and then was /tmp mounted with noexec. I checked for that but it was ok... On a whim I decided to set my tmp dir to another location and it worked:
TMP=/u01/tmp; export TMP
Update: I recall why changing the TMP directory worked. The problem was with noexec as one of the mount options of /tmp. I had changed it in fstab but couldn't arrange downtime so I used environment variables to repoint tmp. The server still hasn't been rebooted, so the change hasn't come into affect yet.