[Porsche-O-Phile]

Exactly what Paul & Chris said - I'll bet your problem is related to hydrostatic pressure buildup and the absence of either a French drain or perforated clay pipe to drain outside the foundation wall-to-footing connection (in other words either a cheapass contractor or a *****ty detail). The only way to permanently (and properly) fix the problem is to excavate a trench on the outside of the wall to about the depth of the footing, install a French drain or clay pipe to drain and backfill (preferably with pea gravel).

Best of luck - I'd consider waterproofing the exterior of the foundation wall while you have the excavation open if it isn't already as a secondary preventive measure too. . .