Hi,
I had went thru the datasheet of P89V51RD2xx but failed to find any thing mentioned about P89V51RD2FN... there is P89V51RD2BN and P89V51RD2FA, but definitely not 'FN'. I assume you are using a 40 pin DIP versions from NXP. (Please be assured that i am not doubting you but just pointing out something that was missing from the datasheets.)

Now i have went thru some suggestions and i even came across some thing regarding PSEN. My friend, for the time being you can keep that pin floating in the air. Yes, here we are talking about P89'V'51RD2xx devices not P89'C'51RD2xx pieces. V-version doen't require toggling of signals on that pin. You may pull the 29th pin out of the dip socket and leave it hanging. while you experiment further.

A loop-back test if done before Max232 (looking into the controller board from PC side) does guarantee that your serial cable completes an electrical loop but doesn't tell you whether you had mixed up the Rx and TX pin assignment. (You could have used a cross cable instead of straight and still get that loop back test right.)
Do the loop back test by removing the microcontroller and shorting the pad numbers 10 and 11 (make sure that pin#10 is connected to either 9 or 12 of MAX232).

Now you definitely doesn't require a CRO for all these. Trust me. (Ever wonder how somebody developed the first CRO without using one!!!).

Use the terminal utility on Flash magic. now select a baud rate say 9600 and keep caps lock on and send 'U' continuously. Now toggle the device power or do a hard reset and see if the uc echos back 'U' character. If you do receive 'U' then you can simply cancel the terminal and try to program the device using Flash Magic set at 9600 bouds (hope you disable the auto ISP mode in FM's settings.).
If you do not receive any echos then you might be require to check your wirings...like the EA pin is connected to VCC or not (A pullup doesn't work sometimes !!!!), is there some short between 10 and 11th pin of uC. Check the power supply. Is it between 4.5V and 5.5 Volts? Is your PC's ground and boards ground connected? Is the Reset circuit functional? What is the voltage that appears on 30th pin. Well when measured using a DC voltmeter it should give a reading around 2Volts?(a crude way i know.)...

And if you have done all this ... :(, sorry to spoil your mood just by reading this crap. else EnJoy good programming.