I have just discovered what causes the "Credit Card Type not found" error in VirtueMart.

First problem : the "Credit Card Type" drop down box isn't displaying...this lead me to the 2nd problem, which is

Second problem : A javascript "writeDynaList" function is required, but is not included in your current javascript functions. So where will you find it?...moving on to the third problem

Third problem: the "writeDynaList" is inside the "JURI::root(true).'/includes/js/joomla.javascript.js'", but the javascript file isn't loading. WHY NOT?

The explanation can be found through this snippet of code in your <joomladirectory>/includes/application.php, and string search for this condition:

if ( $user->get('id') ) {
                    $document->addScript( JURI::root(true).'/includes/js/joomla.javascript.js');
                }
}

This means, that the user has to be logged in to load the javascript file.

If you want to force your customers to login during checkout, go to:

Administrator->Component->Virtuemart->Configuration->Global->User Registration Settings

then set the value of "User Registration Type" to "Normal Account Creation"

Hope this post helps you. Cheers!