My Gateway can not interpret variables set earlier in a script Task !!

[lobnakh]

Hello !!
I think im confused a bit, should a sequence flow condition expression be readily able to read a variable set in a script task earlier in the workflow? Do I need to reference this somehow or are all the variables set within different sections of the workflow sharing the same namespace? And if so would the following conditional statement within the sequence flow be enough to progress onto the next task?
My error was : org.activiti.engine.ActivitiException: Unknown property used in e expression: ${Validate == 1}
Knowing That i used the variable "Validate" as an integer variable in an earlier ScriptTask . Someone can help me to resolve it ??Any example would be appreciated.

Regards
LobnaKh

[lobnakh]

I resolved the problem by adding this line :         execution.setVariable("MyVar",Validate);
Now, a new problem appears : when i start the process, my scriptTask as the first task in my process can not be seen as a Task .
this line of command :  Task task1 = taskService.createTaskQuery().singleResult();
Task1=null which causes a nul pointerException after .
What should i do in this case ???