[plt-scheme] eval question

Hi All,

I am using eval-string to execute a procedure in a module.  The 
procedure is in another module.

For example:

((eval-string
       "(lambda(connection) (my-procedure connection))")
       connection)

my-procedure is in my-collection.  When this executes  I get an error 
stating that my-procedure is not found.  I know that this is a namespace 
issue but I am not sure how to solve it.

Thanks in advance,
Arend