Why can't I edit variables from the 'Edit: Estimated Parameters' window?

Error occures while working with Simulink Design Optimization using the Parameter Estimation GUI.

After I chose the parameters to be estimated, I want to edit them to set e.g. the max. and min. values. To do so, I open the Edit:Estimated Parameters window. Then when I click on the yellow button, that is supposed to show me the variable's values in the excel-like view, a few(~six?) errors pop up. I attached a screenshot of said scenario. Strange thing is, that this does not happen everytime. Sometimes everything works just fine. But most of the time it doesn't.

Thanks in advance for your help

[Fabian Gock]

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