[Andreas]

Replace

PHP Code:

// Check if we have an external URL
if (!($permissions['custompermissions'] & $vbulletin->bf_ugp_custompermissions['canuseexturlsinsig']))
{
    $myparser->parse(convert_url_to_bbcode(strip_bbcode($signature)), 0); 


with

PHP Code:

// Check if we have an external URL
if (!($permissions['custompermissions'] & $vbulletin->bf_ugp_custompermissions['canuseexturlsinsig']))
{
    $myparser->parse(convert_url_to_bbcode($signature), 0); 


and check if this works.