svccfg list
If you see/TEMP/application/management/hwmgmtd listed in the output then delete the file by typing the following:
svccfg delete TEMP/application/management/hwmgmtd
svccfg list
You should no longer see TEMP/application/management/hwmgmtd listed.
pkgrm SUNWssm-hwmgmt-config
You should now be able to install SUNWssm-hwmgmt-config.