There are 2 known causes of this error:

1. Incorrect use of the FormEx property

   FileUp includes two objects that provide the functionality of the ASP Request.Form object, but can understand the encoding type that is specific to file uploads (multipart/form-data). The two objects are Form and FormEx.
   
   Form is used to access the values of solitary form elements. FormEx handles collections of form elements (e.g., listboxes, radio buttons, multiple files, etc.).
   
   This error may occur if FormEx is used to access a form element that is not a collection.
   
   

2. Configuration issues with COM+

   If you have FileUp in a COM+ package, this error can also be caused by something in the security configuration in COM+ not allowing access to the FileUp dll.

FormEx solution

• In a "For...Each" statement, i.e., "For each item in upl.FormEx(multipart)"
• With collection index numbers, i.e., "FormEx("name").index"

COM+ solution

Either troubleshoot your COM+ security settings, or if you do not need to have FileUp in COM+, simply remove the package:

1. Stop the web server completely from the MS-DOS command prompt by typing "iisreset /stop".
   
   
2. Uninstall the SA-FileUp package in COM+:
   1. Open the "Component Services" located via the Control Panel/Administrative Tools.
   2. Navigate to the SA-FileUp Package: /Component Services /Computers /My Computer /COM+ Applications /SA-FileUp
   3. Right-click SA-FileUp. Select Delete.
      
      
3. Register the dll manually:
   1. At the MSDOS prompt, navigate to the directory containing the FileUp dll (usually either C:\Program Files\SofArtisans\FileUp or C:\Program Files\Software Artisans\SA-FileUp)
   2. Then type "REGSVR32 SAFILEUP.DLL"
   
   
4. Restart the webserver: type "iisreset /start" in the MS-DOS command prompt