Installing extension pack

Hello,

Can someone help me ?

I'm trying unsuccessfully to install an image processing extension pack version 3 on Mathcad 13.

The message error (XP operating system) is :

General File Transfer Error :
Setup returned erro code -51 while copying file C:\Program Files\MathSoft\Mathcad 13\tifflib.dll

Thank you for your help.
Regards

Andr�s Revuelta