[TYPO3-english] Error Install DBAL

[Joko Nurjadi]

Dear all,

I'm using Typo3 ver 4.2.6, and try to install extension Backend - Database Abstraction Layer (dbal), but it returns error:

Fatal error: Call to a member function admin_get_charsets() on a non-object in D:\xampp\htdocs\typo3\t3lib\class.t3lib_install.php on line 456

So I have to delete the cache and configuration from localconf.php, my dummy question is, so how to install dbal? Thanks.

Rgds,
Joko