Oracle Database Discussions

I am trying to do a data pump import on a Sun OS box. I have a dumpfile that is no longer owned by the Oracle user, or the group the oracle user belongs to. What file permissions are needed on ths dumpfile for data pump import to work. Here is the error I received:
Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.2.0 - 64bit Production
With the Partitioning, OLAP and Data Mining options
ORA-39001: invalid argument value
ORA-39000: bad dump file specification
ORA-31640: unable to open dump file "/cdwprd/cdwdp/dat/medstg_exp_ddl_200701221435.dmp" for read
ORA-17503: ksfdopn:3 Failed to open file /cdwprd/cdwdp/dat/medstg_exp_ddl_200701221435.dmp
ORA-17500: ODM err:ODM ERROR V-41-4-0-0-6 No such device or address

The file has read permissions for everything:

ls -l /cdwprd/cdwdp/dat/test.dmp
-rw-r--r-- 1 rhaberko cdwprd 172032 Jan 22 14:35 /cdwprd/cdwdp/dat/test.dmp

What more does it need to work properly? The database directory object is pointing to the correct directory. The db user has been granted read, write to this directory object.