dll error

[C# Programming]

i have encountered this error in my program, i don't know how to solve it
pls can someone help.

Error 1 The type 'Sosinpw.SheetStatus' exists in both 'd:\projects\necoscan\necoscan\obj\Debug\Interop.Sosinpw.dll' and 'c:\Program Files\DRS\SKW\Interop.Sosinpw.dll'


thank you.