Simulink and NI-Daq PCI-6251

I can't seem to make Simulink recognize the device, while the script using the usual commands (see below) works just fine. Moreover, on another disk the same Simulink model worked great with the same version of matlab (2012b, 32-bit). But now I can't even tweak the settings in the "Analog Input" block (which is the starting block of the whole diagram and it complains that "Data acquisition device 'nidaq Dev1 (PCI-6251)' is unavailable. The 'winsound 0 (Microphone (high Definition Aud)' device will be selected"

Thanks in advance!

-Mike.

Here is the output of

devices = daq.getDevices

>> devices(1)

ans = 

ni: National Instruments PCI-6251 (Device ID: 'Dev1')
   Analog input subsystem supports:
      7 ranges supported
      Rates from 0.1 to 1250000.0 scans/sec
      16 channels ('ai0' - 'ai15')
      'Voltage' measurement type

     Analog output subsystem supports:
        -5.0 to +5.0 Volts,-10 to +10 Volts ranges
        Rates from 0.1 to 2857142.9 scans/sec
        2 channels ('ao0','ao1')
        'Voltage' measurement type

     Digital subsystem supports:
        24 channels ('port0/line0' - 'port2/line7')
        'InputOnly','OutputOnly','Bidirectional' measurement types

     Counter input subsystem supports:
        Rates from 0.1 to 80000000.0 scans/sec
        2 channels ('ctr0','ctr1')
        'EdgeCount','PulseWidth','Frequency','Position' measurement types

     Counter output subsystem supports:
        Rates from 0.1 to 80000000.0 scans/sec
        2 channels ('ctr0','ctr1')
        'PulseGeneration' measurement type

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

The code below runs without problems.

devices = daq.getDevices

devices(1)

s = daq.createSession('ni');

s.addAnalogInputChannel('Dev1', 0, 'Voltage'); 

s.Rate = 8000

[data,time] = s.startForeground;

%%Plot the Acquired Data

plot(time,data);
xlabel('Time (secs)');
ylabel('Voltage')