Depends on how you have the backup of dts.
If you have dts as .dts file use EM....
you can't overwrite a package.. you have to delete or rename the package before you load from file...
Right click DATA TRANASFORMATION SERVICES/Open package/provide the path...
If you have multiple packages on another server you can use DTS to copy the msdb..sysdtspacakges table to copy the packages...
Transferring DTS Packages
http://www.sqldts.com/204.aspx
MohammedU
Microsoft SQL Server MVP