capture problem

Hi

I'm trying to capture video on my mac laptop: powerpc G4, 1.33 ghz, 1 GB Ram, FCP 5.1.4. I've worked on FCP on this computer for ages, so quite proficient with the basics of FCP editing. Now, suddenly when i don't believe i've done anything different to my settings and in fact have quadruple checked them...it's not working. Every time i try to capture whether it's capture now or batch, it's telling me my scratch disks are full. I'm trying to capture to my G-RAID which has 50 GB available, plenty...i've tried testing with various capture batch sizes, even as little as 10 seconds and it still gives me this error that my scratch disks are full!?? i even tried capturing straight to my computer, to see if it was an issue with the drive.... again same error. i've never experienced this, any one now what's up?