Using Windows 7 (64) and MathCast v0.9 I have not been able to export formula as png files. But I can export as bmp.
I would prefer to work with png files. An I doing something wrong ?
You might have discovered a new bug. (MathCast might not have write permissions in it's folder.)
Please try to copy mathcast's folder from "C:\Program Files\MathCast" or "C:\Program Files (x86)\MathCast" to another folder such as "C:\MathCast" or to your Desktop or to your Documents folder (The entire folder with all the files in it.) Then run MathCast by double-clicking on MathCast.exe
Tried the suggestion of moving MathCast to a new folder c:;\mathcast\ but the same problem remains. I notice that when I do a file search for the "formula.png" file the name shows up but no file can be located in the folder. This seems to suggest that file was being created but not created !!! Hope this helps.
I still think it's a folder permission thing. Did you try copying the folder to the "Documents" folder. also make sure you run "MathCast.exe" and not the MathCast icon from the "Start Menu".