The first errors you posted were about missing tables. On new installations its expected to log errors like this because the tables don't exist until after setup runs. The error you see on the setup page is the relevant error.
I think you are dealing wth either one of 2 possible problems.
First is some bugs in the install script brought to my attention in this thread. The bug only affects some installations of MySql so I had not noticed it. On installations where MySql is configured to force lower case table names, no bug happens but on systems that keep the mixed case tables this bug happens. I think this is the problem you are dealing with because it looks like its trying to create the table mp_Pages which is mixed case. I have already fixed the bug in svn trunk and will be making a new release soon, but you can fix it right away if you use a text editor and open the file /Web/Setup/applications/mojoportal-core/SchemaInstallScripts/mysql/188.8.131.52.config and replace all instyances of mp_sites with mp_Sites using a case sensitive find and replace, or manually editing each.
Second is MySql 5.1 doesn't work as discussed in this thread. Only solution here is to go back to MySql 5.0
Hope it helps,