If the cuttings were dormant when taken, rooting can be difficult. If the cuttings were placed in water to force the new growth and have not yet rooted, there is one method that may work. When the new growth is about 3-6 inches, clip the excess hard wood above and below the growth leaving about an inch or so of hard wood. Place the cutting in a rooting mixture and keek it damp, in partial sunlight/shade area. Root warming also might help. I am doing this with hardy kiwis with about a 50% success rate.

Yeah, may take a little more time. My red flame cuttings this year are well on the way to leafed-out but have only tiny stubs of roots so far.

Most of them I just stuck in a nursery pot full of peat moss. Some I stuck in pots that contain dirt which is mostly clay and sand.

Almost 100% success with over 20 cuttings. One of the easiest things I have ever propagated.

No help with grape cuttings since I've never tried rooting any
But I see the same thing a lot with vine cuttings
They'll sprout new leaves & start growing
But no roots when you go to transplant them

Suggestion that might help
Start them in plastic cups & transplant them when you can see the roots against the sides on the cup
Or
Use something like rockwool or peat pots & pot/plant them when you see roots starting to grow through

Good Luck

And you are POSITIVE that you planted them right side up? Very easy to get grape cuttings turned the wrong way when taking a bunch of cuttings.

You really need to describe the exact method you used to propagate your grape vine cuttings before any realistic comments can be made.
What propagation media did you use?
Did you use any rooting hormone?
If so, was it a power, liquid or jell?
Where they placed in a controlled temperature and humidity environment?
How long did you wait before you check for roots?
What amount of light were they given?

Hans P. Gruetzenbach
'The Gardener Guy'
From GrapeVinesAndMore.com

Hi Everyone,
Thank you so much for your thoughtful comments. It's been a couple months now since I posted, so I wanted to let you know how it went. Basically, I have had about a 30% success rate with the grape cuttings. I think more of them would have survived except that a couple got cut down by "helpful" friends who were doing some weed-wacking. Also, we had a long spell of hot weather (95 degrees +) before I had set up the irrigation system, and I did not have time to hand water them as much as needed. So, given those factors, I think 30% success is not too bad.

Next time around I would definitely wait longer to transplant them, knowing that leaves are not necessarily an indication of roots. I also really like the suggestion of planting cuttings in clear containers, so I can see what's going on with the roots.

In answer to "Rhizo" and "Gardener Guy," the cuttings were a gift, so I do not know the details of how they were originally planted.

Did you ever get an answer? I gave the same problem !