Is there something particular you're performing when accessing these pages? Unfortunately, I am not seeing these errors directly by accessing them.
#1 you likely are missing a file if you're still seeing this error so you'll want to upload all files from the Client Area again.
The rest of these look like they could be database related. Did you have any errors during install?
We would need to look further into this for you, however the access details on file appear to be incorrect or missing. Could you please update these details by visiting your client area, selecting the relevant purchase, then clicking "Review/Update Access Information" under the "Stored Access Information" section.
We look forward to further assisting you.