%s - url insert

[kargo0]

Hello everybody,
I search but I've not found. So I'm here!
I'm working on Joomla 2.5.6 and Virtuemart 2.0.18a with french langage pack.
When no shipment or payment method are corresponding to customer, or when customer try to select shipment or payment without being connected before, the warning message isn't entire and i've empty link

Code Select Expand

<a href=""></a>
or 

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%s instead of correct redirection.
Iv' tried to change language file encoding, to change joomla's language, to activate/deactivate SEF, nothing works.
Known issue ? Could anyone help me to solve this ?
Thanks !