I get above error for following 2 scripts, what could be reason.
*** Settings ***
Resource resource.txt
*** Variables ***
@{ExpectedCookieValue} selenium1234
@{ExtractedCookieValue} ${Empty}
*** Test Cases ***
CookieTest
Open Browser http://www.google.com ${Browser}
Maximise Browser Window
Add Cookie SeleniumTest selenium1234
Get Cookie Value SeleniumTest
${ExtractedCookieValue} Get Cookie Value SeleniumTest
Log "Extracted Cookie Value"
Log ${ExtractedCookieValue}
Should Be Equal ${ExtractedCookieValue} ${ExpectedCookieValue} 'Cookie Should Be Equal'
Close Browser
2nd Script
*** Settings ***
Resource resource.txt
*** Test Cases ***
AlertTest
Open Browser http://www.seleniummaster.com/robotframeworktest/alerttest.html ${Browser}
Sleep 5s
Click Button name=alert_button
Sleep 5s
Alert Should Be Present This is an alert box
Close Browser