Problem With Package.Execute Passing Variables

I am having a problem with passing variables into my SSIS package from C#. The variable names match ("Variable1, ...), however they do not seem to be assigned the proper values once the package is executed. The package does run and returns a FALURE notice saying there is a problem with my expressions.

When I added a new data flow, derived all the variables into columns and wrote their values to a flat file I noticed that the values still contain my default values from the SSIS package itself as though nothing was passed in from C#. I am hoping that it is a simple configuration/user error.

Any ideas?



---- C# ----

Reference to Microsoft.SQLServer.ManagedDTS

using Microsoft.SqlServer.Dts.Runtime;

Application DTSApp = new Application();
Package DTSPack = DTSApp.LoadPackage("d:\SSISPackages\Package.dtsx", null);
DTSPack.Variables.Add("Variable1", true, "", var1.ToString());
DTSPack.Variables.Add("Variable2", true, "", var2);
DTSPack.Variables.Add("Variable3", true, "", 100);
DTSPack.Variables.Add("Variable4", true, "", var4.ToString());
DTSExecResult pkgResult = DTSPack.Execute(null, DTSPack.Variables, null, null, null);