Need Advice on Use of PST Splitter for Outlook

My memory usage has reached its 2GB capacity. I was trying to delete some of my files to regain some memory space but I simply could not do it because the folder has been locked for some reason I don’t know.
Now I am getting an error with my Microsoft Outlook 2002. I’m wondering whether it is good to use a tool like the PST splitter for Outlook. Which is the best version that you could recommend me? Something that cannot be corrupted.
Thank you so much.
