guys i need your here pls tell me what is wrong with this statement

My Picture column contain this picture\upload\123.gif

VB Code:
  1. path=rs.fields(picture)

  2.  
  3. server.mappath(path)//error line

if i do the above code i will get a type mismatch error

VB Code:
  1. path="picture\upload\123.gif"

  2.  
  3. server.mappath(path)

but if i do this then every thing turns out fine...

What is wrong with this!??