Everytime I execute the startup command the following logs are generated ----
(1) [ OCROSD]utopen:6':failed in stat OCR file/disk /oracle/oragrid/product/db10g/
cdata/localhost/local.ocr, errno=2, os err string=No such file or directory
(2) [ OCROSD]utopen:7:failed to open OCR file/disk /oracle/oragrid/product/db10g/cdata/localhost/local.ocr , errno=2, os err string=No such file or directory
(3) [ OCRRAW]proprinit: Could not open raw device
(4) [ default]a_init:7!: Backend init unsuccessful : 
(5): [ CSSCLNT]clsssinit: Unable to access OCR device in OCR init.
---- any idea about cause /resolve
Please post more details ?
Which oracle product you are trying to start ? Oracle Version ?
Command used to start etc.
From logs it looks like you are not able to access OCR disk . Is file /oracle/oragrid/product/db10g/cdata/localhost/local.ocr available ?
Also this forum is related to OEM , please post these questions in RAC forum.