There could be misalignment of the pulleys .... but thats doubtfull unless
you had an alternator or other accesory replaced recently .... the most
likely cause is the belt lost tension shortly after being installed ... this
happens to all new belts ...  since the 626 does not have an automatic belt
tensioners the belts should be re-adjusted approx 1 week after installation
and maybe in 2 weeks after that again.... if left unattended the belt will
slip and come apart quickly ...  aftermarket belts seem more pron to this
...  are you using factory belts ?? if not try a set .. as a bonus the
factory belts are usually cheaper than some aftermarkets ....