Unfortunately I have never used either of the programs you mentioned, but I would bet you are making a very common mistake… pathing problems.
Does the Web gallery work just after you created it? If yes, then almost any malfunction can be traced to pathing problems.
As a learning experience, I would suggest that you get out of expression web mode and learn the file/folder structure created by Adobe Lightroom for your web gallery. Not sure how you are uploading your “web gallery” but I would suggest using an FTP program like SmartFTP. This will visually let you see file/folder relationships and could alert you to problems.
Any change in the original “RELATIVE” relationship will cause problems. For example, if you put a .swf into a Web page that is one folder level above all the supporting files, you will have to change the .swf to find the required files, which now, relative to it’s location, are one folder level below. If your .swf calls an xml file, it is now one layer above it’s original location, so you need to address that. If you cannot change the actual Flash .fla file, never change the file/folder relationship. If you but the .swf in the root of your Web site, all the other files need to be put in there also, in the file/folder relationship as originally created.
In creating .swfs, I often have to create extra folders which will exist when it’s in its final location.
Then back to expression web 2. Once you have the correct file/folder structure, just open the file with the .swf…and things will work just right!
Eye for Video