A dialog box is open. Close it and try again.
I recently had to set up a new laptop with all the development tools and other applications. This in itself isn't so bad, it just takes some time. This was also my first hands-on experience with Vista, and Vista 64-bit nonetheless. It made for some pretty interesting driver searches and downloads and in the end all worked out fine.
With the exception of Outlook 2007. I opened Outlook and it created an account to the Exchange server. All seemed well and Outlook even downloaded my email from the Exchange server. Outlook even allowed me to read my emails. However, I could not compose new emails, nor could I reply to the ones I read. Every time I tried, I would get this error message: "A dialog box is open. Close it and try again."
Searching for this dialog box was unsuccessful. No amount of Alt-Tab, or switching to Outlook from the task manager would show it. Of course I moved the actual Outlook window around also, but nowhere was there a sign of a dialog window. I closed all applications and tried to close Outlook also, but was greeted with the same error message. I had to stop the application using the TaskManager. I rebooted and tried a number of times, all to no avail.
Thus I Googled and found this article: Hidden dialog box in Outlook 2007 problem.
This forum post was spot on. It turns out that every time Outlook started, it tried to create a new account for me. During this process a dialog box showed that asked my name and Initials, but it was hidden immediately. The advice from the post helped me out:
I ran into this same problem today. Upon starting Outlook 2007 after loading a new account I received this error. I believe the dialog box being hidden was where it asks for users initials and name as it flashes fast and you cannot click ok.
To get past this I opened another program in the suite such as Word 2007 where that same dialog box pops up. I enter the information and clicked ok and that appears to be universal throughout the whole suite. I then got back into Outlook and I could perform the necessary functions.
Another poster commented:
I had the same problem with Outlook and the hidden "Name and initials" dialog box on new profiles. It was caused by the recent Outlook patch KB946983. Removing it fixed the problem.
Reading through all the posts is quite interesting. Also, for future Outlook patch/upgrade issues, you can check out the Office Sustained Engineering blog of "the team behind Office hotfixes, security updates, and service packs".