Buttons with Led's

Hi,
I have some problems with a csv script.
I'm using a HD1010.

I connected 4 buttons th the unit. The swithes are coonected to the Button 0,1,2 and 3 inputs. I connected the 12 volt led's in the buttons to the Button 4,5,6 and 7 lines using a optocoupler.

The purpose of all this is to start a film clip by pressing one of the buttons. In the idle state all te led's in the buttons shoult be on.
While playing a clip only the selected button shoult be lit.

In the script i use all the clips play well after pressing a button.

However, in idle state none of the led's are lit. The led's in button 1,2 and 3 are lit while playing the clip. The led in button 4 does not.
On the terminal connected to the serial port i can see that output 4,5 and 6 are enabled. Output 7 is not.

This is the script i use:

IMAGEMODE,1,,,,,,
VIDEOMODE,1024x768x75p,,,,,,
,,,,,,,
GPIOENABLEOUTPUT,7,,,,,,
GPIOENABLEOUTPUT,5,,,,,,
GPIOENABLEOUTPUT,6,,,,,,
GPIOENABLEOUTPUT,4,,,,,,
,,,,,,,
EVENTS,,videoend,button:0,button:1,button:2,button:3,timeout:30
STATE,01_StartFrame.bmp:gpiosON(4;5;6;7),,1992_Stier_Herman.ts,1993_Stier_Herman.ts,1996_Stier_Herman.ts,2008_Stier_Herman.ts,
STATE,1992_Stier_Herman.ts:gpiosON(4),01_StartFrame.bmp,,,,,01_StartFrame.bmp
STATE,1993_Stier_Herman.ts:gpiosOff(5),01_StartFrame.bmp,,,,,01_StartFrame.bmp
STATE,1996_Stier_Herman.ts:gpiosOff(6),01_StartFrame.bmp,,,,,01_StartFrame.bmp
STATE,2008_Stier_Herman.ts:gpiosOff(7),01_StartFrame.bmp,,,,,01_StartFrame.bmp

I hope you can help me.

Regards,
Frank