Do you maybe still have some older extensions installed? The files it says it can't find aren't even used in the latest versions, so it appears to be an issue with some files not being removed from your original installation.
Do you have a lot of other extensions installed? You may want to try re-naming your user Configuration folder and re-installing all of the extensions.
If you do that, then make sure to install eCart first. Another option, since it happens at startup is to try deleting or renaming just the /configuration/startup folder. I don't think we use any files in that directory any more so the leftover files there are the likely culprit.
Did this help? Tips are appreciated...
