PDF Xchange has been working for me with no problems
...with Avast v4.8? Or with v6.0?
@
tlee,
If the problem was a database update, it may be solved in future updates.
In the meantime, maybe you could find a workaround, like for example using a portable PDF viewer/reader. Being portable, it should give you a simple interface without messing with your current Windows settings. When the problem would be solved in Avast databases, then you simple delete the folder of the protable PDF viewer and you continue with your usual program, PDF Xchange.
Of course, if you also need edition of PDF, that may be "more complicated" to temporarily workaround.
For portable PDF viewers, there are many options. Ask here if you are interested.