update column in access table

[proteome]

I am trying to update a column in an access table by using a public function:

Code:
Public Function Create_web_URL(ByVal data As String) As String
Dim url As String
Dim result As String

url = "

http://www.web.edu"

result = url & data
Create_web_URL = result
End Function

data is a column in the table I am trying to update

I am using the following sql to try and update the column

strsql = "Update table2 SET url = Create_web_URL (data)"
acAccess.CurrentDb.Execute(strsql)

The problem is I keep getting that Create_web_URL is an unknown function

Please Help