SSIS Package error

I am trying to run a ssis package and I get the following error message :

Failed to lock variable "intDelayTime" for read access with error 0xC0010001 "The variable cannot be found. This occurs when an attempt is made to retrieve a variable from the Variables collection on a container during execution of the package, and the variable is not there. The variable name may have changed or the variable is not being created.".  
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I have declared the variable intDelayTime as Int32 in the variable list but still I get the above message. Please help. Thanks.