grub error 22

Have used Kubuntu on the loop file , but it was limited to 4 Gb. Therefore , I should risk the partitioning. It was successful , but the new partition was logical and I cannot start Kubuntu . So I converted the partition to primary. Now I have 3 working partitions ( fully working , accessible from Ubuntu started via live CD ). But GRUB stops working . It just writes " stage 1.5 " and "error 22" . I tried to setup GRUB , reinstall it , without change. How can error 22 be fixed ?