SSIS Tasks Execution Order Problem

Hi,

I'm facing a problem with my SSIS package regarding the execution order of tasks. I am using my package for the purpose of loading data from XML to staging tables in the database, and have a loop to process all XML files.

As a precondition to the loading action itself, I am running a stored procedure against the database (using the ExecuteSQL task) to check whether all staging tables are empty. The output parameter of that stored procedure is mapped to a variable I have defined in the SSIS package, so I can use it as a basis for the decision whether to run the loading action or not.

In order to test my package I added a script task, right after the execution of the stored procedure with a precedence constraint, that pops up a messagebox with the value of the stored procedure return value stored in the package variable.

The problem is that for the first iteration of the loop, the variable value presented by the messagebox is incorrect (equals to the initial value I assigned to the variable), and it looks like the script task starts before the stored procedure execution task finishes and its output value is stored in the package variable.

Please assist.