>>>No, I think. The correct UNC path must be something like "\\MyWorkstation\C:\DTS\DTS__SomeFile.dts"
>>
>>Nope. A UNC is formed in the template:
>>
>>

\\<Server Name>\<Share Name>

>>
>>Server name and share name cannot contain either : or \ characters. It's strongly suggested that the Server Name (AKA Machine Name) and Share Name use no more than 15 characters with no delimiter characters, and if Win16 compatibility is an issue, 8 characters.
>
>I tried API function PathIsUNC() in shlwapi.dll and it returns OK.

Try using it with NET USE or WNetAddConnection2()