Portable upright air conditioner water drain?

i have a portable upright air conditioner that has 2 hoses you put out the window,,,the first year i had it i didnt have to drain it once,,,the next year, it seems every 4 or 5 days its leaking from the drain plug and ruing my hardwood floor,,why might this be? it is driving me nuts, and when it comes to anything mechanical, i have the iQ of a gfruit any help would be greatly appreciated