This is what helpdesk answer:
2 I've inspected your cart and found out that you added the following code to the value of the 'txt_welcome' language variable:
<img height="480" src="{$ImagesDir}/pilot.jpg" width="640" />
Smarty tags (i.e. "{$ImagesDir}") cannot be used in the values of the language variables.
I replaced the code with this:
<img src="skin1/images/pilot.jpg" width="640" height="480" />
and that solved the issue.