Warning: Cannot modify header information - headers already sent by: Drupal/mySQL Error

I changed the Charset of mySQL DB to see if I could get rid of the error im phpmyadmin and it gave me error messages immediately (this attempt is detailed in a different account on my website), but when I switched it back to Latin1 (phpmyAdmin keeps saying Swedish Collation), it worked for about a day and I think that I installed a module that ran an SQL command that clashed against the existing mismatch dues to flipping the Charset midway.

Update:
This error message also appears to be related to the Flexinode Module - See this entry.

PHPmyAdmin Settings
At the beginning, I did not pay attention to the Charset that this application was working in and largely ignore the alert it had on the opening page informaing me that I needed to enable MBString support in PHP so that it could join tables and strings properly.

mySQL DB Admin settings
Working with multiple formats (InnoDB, myISAM etc), I did not pay attention to the Charset after selecting Latin1 in the setup wizard (to mainly support English and Latin languages), in quest to resolve the issue in phpmyadmin, I ended up changing the charset to UTF-8 and when this did not work, and when it started giving me errors soon after the change and behaving like it could not read some DB tables (it had the default template and did not see some block settings), I quickly switched it back to Latin1 - Swedish Collation. I think that the damage was already done even though I did not know it until about 36 hours later after I had tinkered with all the modules that I wanted to try.

DB Failure Details
I did not know that the DB had a problemuntil I logged off for the day and it all fell apart. For some reason, everything works OK while logged in (even now it works when logged in), but fails immediately I log off and with every refresh comes more error strings and some junk-characters down the page.

Resolution
Having quickly glanced online to see if there are any quick solutions, I decided to bite the bullet and rebuild the database, slow and clean for production. I also take the lesson that I should generate SQL backups of all my tabled and individual important tables regularly when I get to milestones.

Going Forward
I will keep making backups of my work as I go ahead and I will do a whole lot more research on the workings of mySQL and other major databases so that such a crash does not send me rebuilding after I get the production system to run with a whole lot of content.

NB: I still have to resolve the DB lockup issue, although I see that whenever I am running both phpmyAdmin and the mySQL administrator, it occurs more frequently.

_____________________Here is the complete error message_______________________

Notice: Undefined index: module in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 86

Notice: Undefined index: module in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 335

Notice: Undefined index: filter in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 93

Notice: Undefined index: statistics in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 335

Notice: Undefined index: system in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 335

Notice: Undefined index: system in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 93

Notice: Undefined index: user in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 335

Notice: Undefined index: user in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 93

Notice: Undefined index: watchdog in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 335

Notice: Undefined index: watchdog in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 93

Warning: Cannot modify header information - headers already sent by (output started at C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc:86) in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 448

Warning: Cannot modify header information - headers already sent by (output started at C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc:86) in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 449

Warning: Cannot modify header information - headers already sent by (output started at C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc:86) in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 457

Warning: Cannot modify header information - headers already sent by (output started at C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc:86) in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 465

Warning: Cannot modify header information - headers already sent by (output started at C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc:86) in C:\Program Files\Apache Group\Apache2\htdocs\drupal465\includes\bootstrap.inc on line 465
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