Plot ReactorManager preventing Plot Preview

[swong260766]

Hello,

I've written a .dll in C# using PlotReactorManager to display a dialogbox prompting users what account to charge their plots to. It works fine. But when I select File/Print/Plot Preview, it crashes and shows "Fatal Error : Unhandled Access Violation Reading 0x0000 Exception at c49b82h". I searched the web but did not come up with much helpful information. I am using AutoCAD MEP 2011, VS 2010 and I've made sure the Target Framework is pointing to .NET 3.5 instead of .NET 4.0. The app also writes a registry key to HKEY_CURRENT_USER\Software\Autodesk\AutoCAD\R18.1\ACAD-9006:409\Applications\[my app name] in Windows 7. Any ideas what's the problem? Thanks.

Shirley