Can you please post the entire exception?
Also, are you using the MQ Distro installer or the Java ES installer?
Can you please tell us at which point during the installation
did you get the exception? On which screen during the installer
did you get the exception?
If you have MQ 3.5 SP1 installed, it may be a problem during upgrade.
Check the Upgrade/Migration guide to see is your configuration is a
supported upgrade scenario.
If it is a problem with upgrade, try to pkgrm all the SUNWiq* pkgs manually,
then mv /var/sadm/install/productregistry to /var/sam/install/productregistry.sav,
then restart the install.
Thanks.