[TYPO3-project-formidable] FORMidable 0.6.0: XML converting error - prefix not mapped on namespace

[Jan]

Hello formidable users,

i've installed the extension formidable, and use the manual  
manual_formidable_byex.pdf to learn how to configure formidable for  
using in my own extension.

I use the example xml:

<formidable version="0.6.0">
    <meta>
	<name>Dynamische Testform</name>
	<form formid="Testform"/>
	<debug>true</debug>
	<displaylabels>true</displaylabels>
    </meta>
    <control>
	<datahandler:DB>
	<tablename>fe_users</tablename>
	<keyname>uid</keyname>
	</datahandler:DB>
	<renderer:STANDARD/>
    </control>
    <elements>
	<renderlet:TEXT name="username" label="User name"/>
	<renderlet:PASSWORD name="password" label="Password"/>
	<renderlet:SUBMIT label="Submit"/>
    </elements>
</formidable>

the FE formidable debug says "FORMIDABLE CORE - The given XML file ('/ 
home/www/htdocs/jb/typo3conf/ext/et_formidable_test/form1.xml') isn't  
well-formed XML Parser says : XML error: Empty document at line 1 
(Total exec. time: "

the document isn't empty, i've pasted the lines above...

if i try to open the .xml directly with firefox there is an error  
message like "XML converting errror - prefix is not mapped on namespace"
and show me the following line  "<datahandler:DB>"   on line 9 colum 2.

i don't understand why this message this message appear..

Know anybody why this error message appear ?

TIA

Best Regard
                    Jan Bludau