RDBMS software install on a RAC cluster

We have  two node cluster running two instances on each one of them with a database. The grid home and the rdbms home are different as per the seperations of roles etc. We decided to add another database to the cluster-which is not the usual case. But due several other factors, we want to add another database to the cluster.  We wanted a differrent mount point for the rdbms software alone on both the nodes for this new database while using the same grid home.

When i ran the installer to install the rdbms software on the new mount point.. it is giving me the error: that the clusterware stack is not running and as root i need run Gridhome/bin/crsctl start crs.  Any ideas why this error?