VBA Custom Function - Form Control Name Object Not Supported?

I'm creating a custom function to cut down on redundant code. However, in converting the code to a function so that it may be used in different instances, I'm getting an unexpected error when the code executes.

The error is:

Code:
Object doesn't support this property or method.

Here is my function:

Code:
Public Function chkClick(checkboxName As String, tabName As String, chartName As String, seriesNumber As Long)
Sheets(tabName).ChartObjects(chartName).Activate
If Sheets(tabName).checkboxName.Value = True Then
ActiveChart.FullSeriesCollection(seriesNumber).Select

[code]....

The function checks the status of the checkbox name passed to it. If it's checked, it will show a chart series. If it's not checked, it will hide the chart series. The error comes in referencing the "checkboxName".

How might I need to alter the code so that I can use the form control name as a variable? This is ultimately one of the key components of the function as each control has it's own name.