I had one of my developers (Ravindra Khokharia) looked at the issue.
His comments:

1) File - /application/controllers/RegisterController.php
2) Added extra function at the end of file, below
function _printTemplateContent($sTemplateFile, &$redata, $iDebugLine = -1)
{
echo templatereplace(file_get_contents($sTemplateFile),array(),$redata,'survey['.$iDebugLine.']');
}
3) Function name - actionIndex - line no 50

Below code after line number 273 in Register Controller.php

foreach(file("$thistpl/startpage.pstpl") as $op)
    {
        echo templatereplace($op);
    }
    foreach(file("$thistpl/survey.pstpl") as $op)
    {
        echo "\t".templatereplace($op);
    }
    echo $html;
    foreach(file("$thistpl/endpage.pstpl") as $op)
    {
        echo templatereplace($op);
    }

is replaced with below code

$redata = compact(array_keys(get_defined_vars()));
    $this->_printTemplateContent($thistpl.'/startpage.pstpl', $redata, __LINE__);
    $this->_printTemplateContent($thistpl.'/survey.pstpl', $redata, __LINE__);
    echo $html;
$this->_printTemplateContent($thistpl.'/endpage.pstpl', $redata, __LINE__);

Can you please create a gitHub pull request?

Fix committed to master branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=10662

Thank you.

Fix committed to 2.1 branch: http://bugs.limesurvey.org/plugin.php?page=Source/view&id=10670

LimeSurvey 2.0+ build 121204 released.