Thank you for your post.
The first problem has been previously reporte. If you select a Layout beyond the 255th listed, it will select the last layout. However, if you select a layout by number, it will work properly.
I'm not familiar with the second problem. The fact that the number of table occurrences changes each time you launch could point to something memory related. Are you using any plug-ins? Do you have an old backup that was working properly? Please also keep in mind that the Recover option will do its best to try and repair a file. Although most of the time it will fix a file, it may not fix everything, but it should allow you to open the file so you can retrieve the data.
Any other information you can provide may be helpful in narrowing down the possible cause(s).