Qualifying lead to opp ERROR message

I was wondering if someone could help me....

when one of my collgues tries to qualify another users lead to a opp they receive the below message.

I have changed their security roles so they are able to do this.

I am the system admin/customiser when I do it on my laptop logged in as them it works, but when they do it they receive the below error message.

Any suggestion as to why this is?