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XML Expansion Pack or Smart Document Program is Missing or Invalid
http://www.vistaarticles.com/articles/222/1/XML-Expansion-Pack-or-Smart-Document-Program-is-Missing-or-Invalid
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Published on 12/10/2006
 
When you open a smart document solution.

XML Expansion Pack or Smart Document Program is Missing or Invalid

To work around this issue, rewrite the smart document solution .dll file by using one of the following managed code programming languages:

Microsoft C++
Microsoft Visual C#
Microsoft Visual Basic