Can't save to USB flashdrive

[videoprof]

Hi,

I have a brand new 15" MacBook Pro
2GHz Intel Core Duo
1 GB DDR2 SDRAM
Mac Os X 10.4.7

When I try to save a file via USB to my flash drive (I have two from two different companies), I get a message that says the drive is too full. But, the drive has 117 MB of available space! When I try to Save-As to the drive in an application, I get a message that the drive is full or write-protected.

I can view files from the flash with no problem, just no saving.

I have repaired permissions on the hard drive, reset the PRAM and NVRAM, and tried another flash drive. I've also run the flash trough a powered USB hub into the MacBook - no luck so far...flash drive does same thing in each USB port.

Here's the most frustrating thing: the flash drive works great when I use it with my Mac desktop (iMac G4, Mac OS X 10.4.7).

Any ideas?

Thanks very much in advance!

[Giaguara]

Select the info of the drive in Finder (apple-i) - does it show that the drive would be read only, under the General field? Unselect if it has it.
Also, if you see the "ignore ownership on volume" unchecked, check that.