AFAICS the +755 will never work, it produces an error (on SLES 10, anyway). Shouldn't it be
chmod –R 755 /oracle/oracle/product/10.2.0/db_1
? And of course the path used there is supposed to the the Oracle home path, as defined by the Oracle Path set variable; the above is the default if you accept all defaults when you install the Oracle client, but most DBAs will change that, so beware.