Thank you for your post.
This problem has been reported, and I'll assume you were trying to reply to the thread:
At this time, we do not have any additional information, nor do we have a viable workaround. I have attached your post to the original problem report, and I'll keep you posted as information becomes available.
Our Testing Department has sent me the following information:
In Windows Vista and Windows 7, a conflict will occur if you run FileMaker Pro 10 and FileMaker Pro 11 on the same computer with Instant Web Publishing enabled in both versions. Because both versions of FileMaker Pro use the same port number and the same "web.prefs" configuration file for Instant Web Publishing, you cannot run both versions of FileMaker Pro with Instant Web Publishing enabled at the same time. The "web.prefs" file for FileMaker Pro 10 does not work with FileMaker Pro 11, and vice-versa. To avoid conflicts, enable Instant Web Publishing in only one of the versions of FileMaker Pro running on the same computer. If you must switch between versions of FileMaker Pro with Instant Web Publishing enabled in both, you must use the following instructions to delete the "web.prefs" file each time you switch:
1. Turn off Instant Web Publishing in one of the versions of FileMaker Pro and then exit.
2. Delete the "web.prefs" file in: Users\%UserName%\AppData\Local\FileMaker
3. Start the other version of FileMaker Pro and turn on Instant Web Publishing.
In addition, our Testing department would like to know if your installation of FileMaker Pro 11 was done using an Upgrade License Key or a New License Key.
Let me know if removing the web.prefs file works.