The export error is indicating the place in the export that it failed (although not in a particularly helpful way):
The first part 0/4929 shows the frame it had reached in the whole export (in your case 0 as the export failed before it started, after the @ is the timecode position and the length of the project.- the blanks again indicate that the export failed before it had started.
Most likely explanation is a problem with the first clip in the project, or with an effect applied to it. What format is that clip the free tool MediaInfo can tell you about it - a little tutorial thread can be found elsewhere in these forums - here). If it is a format that Studio 12 supports, and that you have used successfully before, there could be one or more bad frames at the beginning; try trimming off a frame or two and try the export again.
HTH
Richard