Digital signature verification throws "The system cannot find thefile specified"

[Carolina]

I have a question and I need some help.

I have an asp.net application which verifies digital signature with
this code:

Private Function Verify(ByVal datosfirmados As Byte(), ByVal
firma As Byte()) As Boolean

Using provider As RSACryptoServiceProvider = New
RSACryptoServiceProvider()

Return provider.VerifyData(datosfirmados, New
SHA1CryptoServiceProvider, firma)
End Using

End Function


Well, this code works perfect when I run my app with a windows account
that belongs to local Administrators group (my app runs under an
Application Pool).

When I change the account to one with no Administrator privileges,
the .VerifyData method returns exception "The system cannot find the
file specified"



What privileges are needed for an account in order to verify digital
signatures with this code?

Any help would be appreciated.

Thanks.