VBA pop up appears since I insert a row in a document

I have 14 rows times’ 31 columns and in each cell there is a check box. There is a control button with an assigned macro in front of every row that allows you to check all the boxes in the entire row. There is also one control button that clears all checked boxes and make them unchecked. All worked fine until I inserted four rows also with checkboxes, but without any macros. Since then every time I want to use control button with macro to check entire row, VBA pop up window appears:
Run-time error `1004`:
Method `Range` of object`_Global` failed

If then I click “End” the macro operation executes as normal and pop up disappears
And if I click “Debug” VBA opens and there is line yellow marked: “Set row_num = Range(cb.LinkedCell)”

Please help me

Thanks Richard. I think the macro should be rephrased then. Can you help me out?

Sub checkme(rownum As Long)

Dim cb As CheckBox
Dim row_num As Range

Application.ScreenUpdating = False
For Each cb In ActiveSheet.CheckBoxes
Set row_num = Range(cb.LinkedCell)
If row_num.Row = rownum Then cb.Value = True
Next cb
Application.ScreenUpdating = True
End Sub
Sub chkrw36()
checkme (36)
End Sub
Sub chkrw37()
checkme (37)
End Sub
Sub chkrw38()
checkme (38)
End Sub
Sub chkrw39()
checkme (39)
End Sub
Sub chkrw40()
checkme (40)
End Sub
Sub chkrw41()
checkme (41)
End Sub
Sub chkrw42()
checkme (42)
End Sub
Sub chkrw43()
checkme (43)
End Sub
Sub chkrw44()
checkme (44)
End Sub
Sub chkrw45()
checkme (45)
End Sub
Sub chkrw46()
checkme (46)
End Sub
Sub chkrw47()
checkme (47)
End Sub
Sub chkrw48()
checkme (48)
End Sub
Sub chkrw51()
checkme (51)
End Sub
Sub uncheckme()

Dim cb As CheckBox
Dim row_num As Range
Application.ScreenUpdating = False
For Each cb In ActiveSheet.CheckBoxes
cb.Value = False
Next cb
Application.ScreenUpdating = True
End Sub