Get error when change order status to confiremed

[salim]

Hi

In ordere section when I select Update Status and set Order Status to confirmed I get this error and email doesn't send.(I get blank page and after enable debug mode I get this error)

Fatal error: Call to undefined method VmVendorPDF::convertHTMLColorToDec() in /public_html/components/com_virtuemart/helpers/vmpdf.php on line 118


In other Order Status option I don't get any error and email is sent correctly.