Error in panel.ggmap

[sm2607]

hi I am using panel.ggmap function in r along with spplot, It was working with old R version, but now I am unable to create a plot and getting "Error using packet 1 NA", and further investigating, issue is due to panel,ggmap function,

panel.ggmap(bgMap)
Error in CRS("+init=epsg:4326") : NA

traceback

4: stop(res[[2]])
3: CRS("+init=epsg:4326")
2: bb2merc(map, "ggmap")
1: panel.ggmap(bgMap)