no, but I managed to solve it and, using the debug tool got rrd to function.. but problem changed somewhat:
a) the summary/network loads shows the traditional "NOTE: this page is not operational when the RRD plugin is disabled, misconfigured or missing." besides it is properly configured/activated (think so).
b) if using the "info about" a particular host (all protocols/traffic, then any host) and click in the "historical data" icon (last line, right), it shows various empty chart, no data at all.
so.. I am still stuck.