On Solaris, the product registry is in /var/sadm/install/productregistry.
In the productregistry file, remove the content between <components> and </components>, and you should then be able to install to the location. The following example shows a product registry file on Solaris.
<productregistry> <version>7.0 </version> <components> <compid>webcore <compversion>1.0 <uniquename>webcore </uniquename> <compinstance>1 <comptype>COMPONENT </comptype> <location>/sun/gj/ws7 </location> </compinstance> </compversion> </compid> <compid>java <compversion>1.0 <uniquename>java </uniquename> <compinstance>1 <comptype>COMPONENT </comptype> <location>/sun/gj/ws7 </location> </compinstance> </compversion> </compid> <compid>snmp <compversion>1.0 <uniquename>snmp </uniquename> <compinstance>1 <comptype>COMPONENT </comptype> <location>/sun/gj/ws7 </location> </compinstance> </compversion> </compid> </components> </productregistry>