I took a data and (apps+media) backup onto sd card, rooted, installed new Rom, and did a factory reset and sd card format, then I copied my backups (zip files) back to Mybackup\AllBackups folder. I now have MyBackup root installed and it does not find anything on the sd card when i try to restore.
Am I doing something wrong? Do I need to install the trial of MBP again?
I did this same procedure when I had to format my SD card in order to partition it. As long as you didn't rename any part of the Mybackup folder structure or file name, it should find the backup files. I've been using MyBackup since last June, and I know at some point, they changed the default name of their folder. I have the latest version, and I see on my sdcard:
/sdcard/rerware/MyBackup/AllAppsBackups (apps)
/sdcard/rerware/MyBackup/AllBackups (data)
Under the AllAppsBackups folder, I see:
/AllAppsBackups/AppsMedia (new location)
/AllAppsBackups/LastBackupApps (old location)
As far as I can tell, the data backup is still under AllBackups. Apps backup got moved from LastBackupApps to AppsMedia.
So my guess is that before you formatted and factory wiped, you didn't have the latest MyBackup App, so it saved stuff to its old locations. You copied that file structure off your SDcard onto your PC. Then, when you installed a new ROM and copied back your SD data, you went to the market and grabbed the latest MyBackup, which is now reading from a different folder structure... It now can't find your backups because it's looking elsewhere. You can try to recreate the new folder structure by making the above folders and using those instead.
Basically, copy everything in LastBackupApps into a new folder called AppsMedia.
I assume your data restore still works? It should, because that location hasn't changed.