I just tried your panel in FSX Paul but it doesn't appear to work for me (I just get an empty tiny black box in the bottom middle of the screen).
I did manage to get a couple of the gauges to work individually in my DC-4 VC though so thanks for that.
I was able to duplicate the black box in the center of the screen phenomenon, and that was if I didn't re-number the [WindowXX] section that I added to the panel.cfg file. I added the panel to the Alphasim T-28, after which the panel.cfg looks like this (added stuff in red):
[Window Titles]
Window00=Main Panel
Window01=Nav Instruments
Window02=GPS
Window03=Nav Panel
[VIEWS]
VIEW_FORWARD_WINDOWS=0,RADIO_STACK_PANEL,GPS_PANEL
VIEW_FORWARD_ZOOM=0.5
VIEW_FORWARD_DIR=1.0, 0.0, 0.0
VIEW_FORWARD_RIGHT_ZOOM=0.5
VIEW_RIGHT_ZOOM=0.5
VIEW_REAR_RIGHT_ZOOM=0.5
VIEW_REAR_ZOOM=0.5
VIEW_REAR_LEFT_ZOOM=0.5
VIEW_LEFT_ZOOM=0.5
VIEW_FORWARD_LEFT_ZOOM=0.5
VIEW_UP_ZOOM=0.5
//--------------------------------------------------------
[Window00]
file=background.bmp
size_mm=1024,768
window_size_ratio=1.000
position=7
visible=1
ident=0
window_size= 1.000, 1.000
window_pos= 0.000, 0.000
//--------------------------------------------------------
[Window01]
Background_color=2,2,2
size_mm=250,494
position=8
visible=0
ident=RADIO_STACK_PANEL
gauge00=Bendix_King_Radio!Bendix-King Radio Audio, 0,0,250,45
gauge01=Bendix_King_Radio!Bendix-King Radio Nav-Comm 1, 0,45,250,91
gauge02=Bendix_King_Radio!Bendix-King Radio Nav-Comm 2, 0,136,250,93
gauge03=Bendix_King_Radio!Bendix-King Radio ADF, 0,227,250,63
gauge04=Bendix_King_Radio!Bendix-King Radio DME, 0,290,250,66
gauge05=Bendix_King_Radio!Bendix-King Radio Xpndr, 0,355,250,72
gauge06=Bendix_King_Radio!Bendix-King Radio AP, 0,426,250,66
//--------------------------------------------------------
[Window02]
Background_color=16,16,16
size_mm=150,250
window_size_ratio=1.000
position=8
visible=0
ident=GPS_PANEL
window_size= 0.240, 0.520
window_pos= 0.000, 0.000
gauge00=gps!gps, 0,0,150,250
// NAV PANEL WINDOW
[Window03]
file=nav_panel.bmp
Background_color=100,100,100
size_mm=310,250
window_size_ratio=1.000
position=2
visible=0
ident=5099
window_size= 0.313, 0.417
window_pos= 0.668, 0.030
gauge00=MRR_NavPanel\01nh_stop!watch, 128,47,72,72
gauge01=MRR_NavPanel\RR Sig Strength meter 2!sig strength, 134,5,56,38
gauge02=MRR_NavPanel\dual-adf-1945!dual adf, 214,75,82,82
gauge03=Douglas_DC3!sperry_autopilot_compass, 7,123,95,120
gauge04=Douglas_DC3!sperry_autopilot_ahi, 104,123,94,120
gauge05=RR_nh_gauges\nh_hsi!Horizontal Situation Indicator, 214,160,82,82
gauge06=ALPHA_A-3!ADF Radio, 7,5,110,55
gauge07=ALPHA_A-3!Radio, 7,62,110,55
...