Screen Capture Problems

I am new to these forums and figured this was as good a place as any to ask this question. I have a macbook pro and I am currently running on Mac OS X Version 10.5.8. My screen capture has recently started to malfunction. Whenever I try (shift+command+3) I get a picture of a blue screen. What does this mean and is there an inexpensive fix for this?

Hi,

I can't explain it. When things start acting a bit strange on Mac it's normally time for some maintenance.
Try clearing out some caches and removing stuff from the desktop, run 'Repair Disk Permissions' on the HDD in Disk Utility. What's your HDD capacity like...you should have approximately 20% free headroom for things to work ok ?

Go here to this great link for further information

http://www.mac-forums.com/forums/os-x-operating-system/93819-basic-os-x-mac-troubleshooting.html