why does File Manager show files in broken icons?

I’ve installed two OS in my PC: QNX and WIN2K, and the file system of WIN2K is FAT32. All of those files in WIN2k can be opened without error under WIN2k, but some of them is displayed in QNX File Manager as broken icons and the descriptions are -1, what’s the problem?
This error troubles me too much since I often have to find help from pdfbooks in WIN2K partition.
Can anyone help? Thx in advance!