In case of using the RadRails IDE on WindowsXP with mysql. If you got an error message like this 'uninnitialize constant Mysql' when command with 'ruby script/generate scaffold Xxxx'.
I don't know exactly why occured this type of error.
To fix it, you must do the following:
1. Goto your mysql home\bin directory : C:\mysql\bin
2. There is only one DLL file. File name is libmySQL.dll.
3. Copy libmySQL.dll file to C:\Windows directory.
All done. Happy Rails ~~