Agent won't work on new box

["Jose Vega" <jvega@xxxxxxxxx>]

Stumped. Checked permissions and access paths.
Moved Domino 6.2 from 270 to 825.

One form has Agent Mgr give "Unable to open file" error whenever we submit form.
Code uses a working directory and attempts to write file.
Code that gives error:
"Declarations"
Const WORKING_DIRECTORY = "/WEB/domino/web/data/domino/HTMLmail/"

"WriteFile"
Function writeFile
        On Error Goto write_File_ERROR
        Dim fileNum As Integer
        fileNum% = Freefile()
        
        If CONVERT_FOR_400 Then
        '       Open FILE_NAME_TEMP For Append As fileNum%
                Open FILE_NAME_TEMP For Append As fileNum%
        Else
                Open FILE_NAME For Append As fileNum%   
        End If

Any help or insight greatly appreciated.