I expect Yvette is right in her interpretation of the error message. Here is some more info about the problem at hand.
1.- It appears that the chunk of text copied from the Wikipedia article (Flesh-Kincaid readability test) is formatted as utf-8. This is not immediately obvious, but there are two utf-8 characters in the last paragraph, the minus signs in "The lowest grade level score in theory is −3.40,..." and "... with a grade level of −1.3." This, by the way, explains why - as mentioned in your screencast - when you remove that last paragraph your question text saves OK in the Lesson! And I was wrong in blaming the Latex bit in the Wikipedia text.
2.- Further to Yvette's remark I conducted the following experiment.
a. As reported in my previous messages, on my local Moodle 2.0 site I do not have the error you mention and I can save my question including the Wikipedia text as a Lesson question text.
b. This is what I did to replicate your problem, on my local Moodle 2.0 test site. My local site is set to utf-8, as required by Moodle. I changed the mdl_lesson_pages table from utf8_general_ci to latin1_general_ci.
c. Then I edited my Lesson question page contents by pasting the last paragraph from the Wikipedia text:
The lowest grade level score in theory is −3.40, but there are few real passages where every sentence consists of a single one-syllable word. Green Eggs and Ham by Dr. Seuss comes close, averaging 5.7 words per sentence and 1.02 syllables per word, with a grade level of −1.3. (Most of the 50 used words are monosyllabic; "anywhere", which occurs 8 times, is the only exception.)
And saved. Got the error message (similar to the one you get):
Error writing to database
More information about this error
Debug info: Incorrect string value: '\xE2\x88\x923.4...' for column 'contents' at row 1
UPDATE mdl_lesson_pages SET qtype = ?,title = ?,lessonid = ?,qoption = ?,contents = ?,contentsformat = ? WHERE id=?
[array (
0 => '3',
1 => 'Flesch–Kincaid Scale',
2 => '1',
3 => '0',
4 => '<p>The lowest grade level score in theory is −3.40, but there are few real passages where every sentence consists of a single one-syllable word. Green Eggs and Ham by Dr. Seuss comes close, averaging 5.7 words per sentence and 1.02 syllables per word, with a grade level of −1.3. (Most of the 50 used words are monosyllabic; "anywhere", which occurs 8 times, is the only exception.)</p>',
5 => '1',
6 => '1',
)]
Stack trace:
line 394 of \lib\dml\moodle_database.php: dml_write_exception thrown
line 980 of \lib\dml\mysqli_native_moodle_database.php: call to moodle_database->query_end()
line 1012 of \lib\dml\mysqli_native_moodle_database.php: call to mysqli_native_moodle_database->update_record_raw()
line 2133 of \mod\lesson\locallib.php: call to mysqli_native_moodle_database->update_record()
line 119 of \mod\lesson\editpage.php: call to lesson_page->update()
Note.- "Incorrect string value: '\xE2\x88\x92" refers to the Unicode value of the "minus" sign used in the Wikipedia article. See UTF-8 encoding table and Unicode characters, page with code points U+2200 to U+227F.
d. Then, I reset my mdl_lesson_pages table back to utf8_general_ci and re-edited the question text, and saved it without any problem, as before the coding switch experiment.
3.- From this little experiment it seems likely to me that your moodle site's database is not set to Collation = utf8_general_ci. Or the mdl_lesson_pages table is not set to Collation = utf8_general_ci (which would be surprising, but...).
I know you have double-checked, but you might like to treble-check (& maybe post a screenshot).
4.- Have you tried the little experiment I suggested in my post dated Monday, 18 April 2011, 11:43 PM:
Try creating a simple "Page" (from the Add a resource menu) in your moodle course, and paste that Wikipedia chunk of text and see what happens.
5.- Is your current Moodle 2.0 site a brand new installation or an upgrade from a previous 1.9 version site?
ATB
Joseph
