Imwheel - can't run without blocking additional buttons

Dear Fedora Users
I have a problem with imwheel which does not run properly. I used many Linuxes like Zorin, Ubuntu and Mint and there was not a problem like this.
I have got next/back buttons on my mouse and I would like them to work during imwheel running. The problem is, that command:

imwheel -kill --buttons "4 5"

returns strange error:

imwheel: ERROR: buttons: #1:   is not a number!

The same thing happens when typed:

imwheel -b "4 5"

Is to possible to make imwheel work properly?

The file imwheelrc contains:

None, Up, Button4, 5
None, Down, Button5, 5
Control_L, Up, Control_L|Button4
Control_L, Down, Control_L|Button5
Shift_L, Up, Shift_L|Button4
Shift_L, Down, Shift_L|Button5