What subversion of virtuoso are you using? (Do help->About in the CIW). There was an issue at one point where the dbLayer functions were snapping to the mfg grid - this was later changed back, and an optional argument added to allow gridding to be performed if needed (see Cadence Online Support Solution 11481956 for more details).
Otherwise I can't see why you'd end up with these small gaps. Also, dbLayerTile produces rectangles/polygons, yet you're talking about paths - I assume this must be related to your other similar post?
Anyway, the best solution is to try to prevent these gaps from happening in the first place. It seems a little odd that there are 0.003 spaced gaps - is the data not on grid in the first place?