Generally speaking, in order for the conditions on the green card provided during the I-526 to be removed at the I-829 stage, the project must have created ten jobs per investor (or be reasonably likely to create ten jobs per investor). Thus, if the jobs do not exist when the I-829 comes up for review, the investor will lose his conditional green card.
The granting of the I-829 is subject to several conditions including the usage of the entire investment capital and the creation of 10 jobs. The 10 full time jobs need to be in existance at the time of filing the I-829 Petition. If the conditions are met, you can still get your I-529 Petition approved. More specific information can be given on a case by case basis.