error while doing the redlining process

hi guys

i was stuck up with duroing the following process.

i have created a document, with a CAD original attachment.

during the redling process, the following erroe is thrown

*Error while checking out:

C:\temp\Layer2_151200.cgm*

1. i am doing the necessary steps?

i am creating a layer1, and making necessary comments on the drawing, while saving the above error message is being thrown.

am i supposed to down load the document and then check it again?????? or i can make necessary correction and save it???????????

pls do guide me

Regards

SURYA