The Republicans knew that if they tried to pass a repeal of Obamacare outright, the Democrats in the Senate would filibuster it to death (i.e., force it to have an unreachable 60 votes). So they decided to do it in a sneaky way -- by attaching repeal to a budget reconciliation bill (which cannot be filibustered). But it looks like they may have screwed that up.
A budget reconciliation bill can only contain items that affect the government's budget -- and one of the parts of repeal the GOP included in the bill does not meet that requirement. The bill contains a provision that requires people who have a lapse in insurance to pay more to the insurance company in the first year after purchasing insurance. The problem (for Republicans) is that provision does not affect the budget in any way. It only affects the size of the premiums that an individual must pay the private insurance company.
The Republicans had included the provision to help insure people don't drop their insurance (and then buy it again after they are sick) -- which would cause premiums for everyone to rise. But if they keep the provision in the reconciliation bill, then Democrats will be able to filibuster the bill (and it would only take 41 of them to kill the bill).
Once again, the congressional Republicans have shown that their most common attribute is incompetence. They have had years to come up with a plan, and still screwed it up.