If anyone is listening ... MySQL is still not working on this Development Machine. I have worked my way through the information provided by Office Guy, but I am still getting those packet 6 bytes shorter than expected and mysqlnd cannot connect to MySQL 4.1+ using old authentication error messages.
I have deleted WAMP twice now; downloaded the latest version from their site; and let the installer rebuild everything from scratch.
Still no joy.
I have also done fresh MySQL queries to build up my tables and databases completely from scratch via those queries, using the new MySQL build, rather than simply copying or importing them. Also no joy.
Then ... I thought it might genuinely be that the old password system was being used instead of the new one. So I decided to test the length of the password. I ran the following query:
SELECT Length(Password), Substring(Password, 1, 1) FROM mysql.user WHERE user=yogastudents362523. This produced a length of 40. Since my original password was only 8 characters, that surely means that the password has been properly hashed and stored by MySQL? Why, then, am I getting the message? I have checked the php.ini file over using the information in the referenced articles from OfficeGuy.
The serious advice given on the WAMP site was to use the WAMP option to revert to a previous PHP build ... which seems to me ridiculous.
I'm fresh out of ideas. Maybe if I just shut down the computer and try again tomorrow, everything will be resolved.