[Discuss-gnuradio] (de)modulation problems gnuradio 3.7.3...also GRC FFT missing axis labels

[rwfisheriv]

I successfully? installed gnuradio 3.7.3 from source on Ubuntu 12.04 using the gnuradio-build script, but am running into problems demodulating anything from a R820T based SDR.  GRC runs fine, but when I attempt to execute any blocks that include an AM, NFM, or WBFM demodulator I get a VOLK:Error allocating memory error.  I also noticed that if I just pipe the RTL-SDR source to a GUI FFT Sink (either QT or WX) there are no axis labels on the graphs....

Attempting to receive WBFM using rtl_fm (per the examples on the rtl-sdr OsmoSDR website) produce only static.  It's not a signal strength issue per se as another radio can pick up  the station, and the SDR hardware is functional since I can receive WBFM with it normally via gqrx on a different machine.

I'm wondering if there's a fundamental problem somewhere that's preventing demod from happening.  Any troubleshooting suggestions would be appreciated. 
Regards,
R