Drools 5.3.0.Final: Fusion broker example contains the 5.2 code (and crashes because of that)

[Line: 56, Column: 28] : [Rule name='If the drop is between 6% and 8%, buy more shares']

Unable to Analyse Expression percent < -0.06:
[Error: Comparison operation requires compatible types. Found class org.mvel2.util.MethodStub and class java.lang.Double]
[Near : {... percent < -0.06 ....}]
I download Drools 5.3.0 Final and try to
run the Broker example that comes with the package.  But I got the
following error, what is wrong?        

               ^
[Line: 56, Column: 28] : [Rule name='If the drop is between 6% and 8%, buy more shares']

Unable to Analyse Expression percent < -0.08:
[Error: Comparison operation requires compatible types. Found class org.mvel2.util.MethodStub and class java.lang.Double]
[Near : {... percent < -0.08 ....}]
                       ^
[Line: 69, Column: 28] : [Rule name='If the drop is on more than 8%, sell shares']

Unable to Analyse Expression percent >= -0.06:
[Error: Comparison operation requires compatible types. Found class org.mvel2.util.MethodStub and class java.lang.Double]
[Near : {... percent >= -0.06 ....}]
                        ^
[Line: 83, Column: 28] : [Rule name='If the drop is between 5% and 6%, do nothing']