Did you ever get an answer to this one?
I've got a similar problem:
I'm getting this message:
"The callee (server [not server application]) is not available and
disappeared; all connections are invalid. The call did not execute."
Application developed in C#.NET
Scenario1: The homepage has a link (href) to a pdf file. When I click the link, everything's fine - the pdf is displayed.
Scenario2: The homepage has a menu link to an external site. Click the link, the external site is opened in a new window. Return focus to the homepage and click the pdf link. Everything's fine - the pdf is displayed.
Scenario3: The homepage also has a menu link to a popup window showing contact details. Click this link and the popup window is displayed. This is a modeless dialog window. Return focus to the homepage and click the pdf link. The page will not open. In the development environment the code breaks with the above message. This happens regardless of whether the contacts popup window is still open, or has ben closed.
I'm not using a popup blocker, so it's not that.