idont know what problem the code is

import rhinoscriptsyntax as rs
import math

pts=rs.GetObjects('get pts')
for i in range(0,len(pts)+1):
    pxyz=rs.PointCoordinates(pts[i])
    for j in range(0,3):
        for k in range(1,4):
            p1=pxyz[0]+j
            p2=pxyz[1]+k
            for i in range(0,3):
                p=rs.AddPoint(p1[i],p2[i],pxyz[2])

Message: 'float' object is unsubscriptable   this is the error,how to sovle,i wanna add tow points round the choosing points