@tom4_u,

You could also try connecting your N900 to a PC with USB mass storage mode (which you already tried but received an error when trying to browse it), and do a CHKDSK on the assigned drive letter?

I suppose I will not work because the drive (MyDocs) is probably not even mapped, but it wouldn't hurt to try?

If it works and you get errors from CHKDSK, try CHKDSK /F to see if the data can be recovered..