Vivien Zepp

I have bought a surfboard rezzer which I have rezzed on group land. I rezzed it in the correct group and have shared it but it only works properly if I am on the sim. When I am not there people are underneath the board instead of being on top of it. Has anyone got any idea why this is happening and how I can correct it? I am unable to deed it to the group as that button is greyed out even though I have the ability to deed. I have the ability to deed objects to group. After I check the 'share' box the deed button is still greyed out.