If you access a wpf browser application via http://myServer/myBrowserApp.xbap (or via the publish.htm file) you cannot open the application but get an error instead. Have a look in the ErrorLog provided, whether it contains the following section:
Below is a summary of the errors, details of these errors are listed later in the log.
* An exception occurred while downloading the manifest. Following failure messages were detected:
+ Exception reading manifest from http://myServer/myBrowserApp.exe.manifest: the manifest may not be valid or the file could not be opened.
+ Application manifest is not semantically valid.
+ Application manifest does not accept specification of publisher or product.
If it contains the error message "Application manifest does not accept specification or publisher or product" check if you have .NET Framework 3.0 SP1 installed on the client. If you have installed SP1 everything will work fine, if not, you will receive the error message above.