Web Pos Problem can't open Terminal

[hotter]

Hello
My ofbiz use V11
When use ofbiz Web Pos-"Open Terminal"
Enter the amount
Click "Do you confirm"
Will show the error message:

Error running the simple-method: Error in simple-method operation [<if-not-empty field-name="parameters.confirm" map-name=""/>]: java.lang.RuntimeException: Error in simple-method operation [<if-not-empty field-name="webPosSession" map-name=""/>]: java.lang.RuntimeException: Error in simple-method operation [<if-compare field-name="mgrLoggedIn" map-name="" value="true"/>]: java.lang.RuntimeException: Error in simple-method operation [<if-compare field-name="isOpen" map-name="" value="false"/>]: java.lang.RuntimeException: Error in simple-method operation [<if-compare field-name="isDouble" map-name="" value="true"/>]: java.lang.RuntimeException: Error in simple-method operation [<create-value/>]: java.lang.ClassCastException: Cannot cast java.lang.String to java.math.BigDecimal<br/>null



Anyone can help?
Thank you!