iLogic rule to detect or create text parameter then fill it out causing Crash

[Anonymous]

This is supposed to check for a custom parameter "Weight" and if it's not there create it. Then once/if a paramter exists it calculates the extents of the model and calculates the mass for the appropriate unit.  It's a bit of a cut and paste job, and had been running into an issue with line 11 where it wouldn't accept "ParameterChecker = oUserParams.AddByValue(Weight, "text",UnitsTypeEnum.kTextUnits)" until I put the paramter value into text. With that change, it now causes Inventor to crash 

doc = ThisDoc.Document
Munits=doc.unitsofmeasure.MassUnits 
Lunits=doc.unitsofmeasure.LengthUnits 
Dim oPartCompDef As PartComponentDefinition = doc.ComponentDefinition
Dim oParams As Parameters = oPartCompDef.Parameters
Dim oUserParams As UserParameters = oParams.UserParameters
Dim ParameterChecker As Parameter
Try
ParameterChecker = oParams(“Weight“)
Catch
ParameterChecker = oUserParams.AddByValue(Weight, "text",UnitsTypeEnum.kTextUnits)
ParameterChecker.ExposedAsProperty = True
End Try

If Lunits=11272 Then 
Volume = (Measure.ExtentsLength * 2.54) * (Measure.ExtentsWidth * 2.54) * (Measure.ExtentsHeight* 2.54)
Else If Lunits=11269  Then
Volume = (Measure.ExtentsLength/10) * (Measure.ExtentsWidth/10) * (Measure.ExtentsHeight/10) 
End If 
materialDensity = ThisDoc.Document.ComponentDefinition.Material.Density
Material_Weight = (materialDensity * Volume)
If Munits=11286 Then
Weight = "(Material_Weight * 0.00220462) lbs"
Else If Munits=11284  Then
Weight = "(Material_Weight) Grams"
Else If Munits=11283  Then
Weight = "(Material_Weight/1000) KG"
End If

[MegaJerk]

Change this line : 

ParameterChecker = oUserParams.AddByValue(Weight, "text",UnitsTypeEnum.kTextUnits)

Into this line : 

ParameterChecker = oUserParams.AddByValue("Weight", "text",UnitsTypeEnum.kTextUnits)

You were not correctly naming the parameter. Without quotes, Weight just looks like a blank variable, and therefore will throw an error.