cannot edit my dts package...(Urgent please)

HI,
I created a dts package using my Windows NT authentication. One of my colleague edited that package last week and when I tried to open it now, it gives me an error message "The system cannot find the file specified". The package still has my NT id as the owner. Could anyone please let me know why is this happening ???
My colleague is still able to edit my package. My NT id and my colleague NT id both are setup as administrators on the sql server. Any help is greatly appreciated.

Thanks
Ramesh