I've got a super-old program called Melody Assistant that I used WAY back in the day to compose some stuff.  I've been revisiting those compositions and trying to bring them to life in Sonar, but I've run into some issues when dragging those MIDI files into Sonar.
 
I'll export the entire song out of Melody Assistant as MIDI (trying both MIDI 1 and MIDI 0 settings offered by the program), then drag that MIDI file into a Sonar session.
 
Those files will play back fine using my Pianoteq soft synth, but then when I copy/drag those midi events into another soft synth like Dimension Pro, nothing happens.  The playback meter shows that something is happening but that's all she wrote, no sound.
 
However, if I manually add MIDI events into that synth track it works as it should...it just seems to be an issue of using a MIDI event created in another application versus doing everything from scratch within Sonar.
 
Any experience with this sort of thing?  Do the MIDI 1/MIDI 0 settings have any impact?

Have a look at MIDI events (in the Event List, not PRV). There can be some "Program/Bank change" messages or some other "SysEx", etc. These messages are thought to select correct instruments and settings which normally works great with TTS1 but can confuse single instrument VSTi (like DimPro).
 
MIDI 0/1 are 2 ways to save original sequence with several tracks: without and with preserving track information.
 

streckfus
 Do the MIDI 1/MIDI 0 settings have any impact?

So you know what you are dealing with, please check here under the title "formats":
 
http://www.midi.org/aboutmidi/tut_midifiles.php
 
Thanks..

Dim Pro doesn't have a patch loaded by default when your first insert it which would explain a new instance being silent. But if you hear newly inserted notes, that wouldn't explain it.
 
I second the motion to look at the events in the Event List View and see if there are controllers or SysEx that might be silencing Dim Pro that Pianoteq doesn't respond to.

streckfus
The playback meter shows that something is happening but that's all she wrote, no sound.

Define "playback meter." Are you saying the audio track using the synth as input shows activity in its meters? Does it show a waveform drawing?

As mentioned above, the MIDI files have extra data in them the sfz engine synths do not like. You can either clean up the MIDI files in the event viewer and/or BEFORE playing the files click on the VST2 header of the synth, open the Plug-in Properties and check the "Do not intercept NRPNs."

Thanks for the feedback, guys.
 
To answer a couple questions, yes, I've loaded a preset from within Dimension Pro before attempting playback.  Regarding the playback meter, I created a simple instrument track so I'm referring to the audio output of the synth.  The meter shows that content is being processed/played from the source MIDI file but there's no audio.
 
Thanks for the additional links and settings info, I'll dig deeper into those and report back if I continue to have issues.