Error while shutting down oracle DB

I am a system engineer working for a private firm. I am mostly into support on a Unix server i.e. IBM AIX server for the clients. In one of the servers, we are using the ora11gR2 and ora10gR2 databases. When I try to shutdown the DB, I am getting an error “could not open parameter file '/oradata3/oracle11g/ora11gR2/app/ora11gR2/product/11.2.0”. This is the first time I am getting an error while shutting down the instances. I will mention the two databases and the instances name as:
“ora11gR2 18974 1 0 01:24:47 ? 0:21 ora_pmon_SOADB”
“ora10gR2 19156 1 0 01:26:02 ? 0:19 ora_pmon_FLEXCJ”
“ora11gR2 19072 1 0 01:25:13 ? 0:19 ora_pmon_FCPBDB”
