The lt table only has one entry per key so lt[j][2] and lt[j-1][2] is always nil (visually the same as using UIParent as the anchor for all frames). Just use _G[lt[j]] or _G[lt[j-1]]
Code:
_G[lt[j][2]]:SetPoint("BOTTOMLEFT",_G[lt[j-1][2]],"TOPLEFT",lt[3],lt[4])
lt[3], lt[4] are the third and fourth key in the lt table, frame name strings or nil depending. Did you mean
Code:
pestartpoint[4], pestartpoint[5] -- -10, 30