Mohammed,
Trying assigning System admin role to the users and check if you are able to create a new record. If you can create one, then you need to dig into security roles to fix it up. But on the other hand, even after assigning admin role, if the New button is disabled, then start debugging the code.
Place the breakpoint in the active() of MarkupTrans DS and check if it turns to be True or False and from there you will be able to find the reason.
Hope it helps!!!