uninstall lr, if it is installed.
then run the cleaner: http://helpx.adobe.com/creative-suite/kb/cs5-cleaner-tool-installation -problems.html
and then retry installing.
uninstall lr, if it is installed.
then run the cleaner: http://helpx.adobe.com/creative-suite/kb/cs5-cleaner-tool-installation -problems.html
and then retry installing.