After further analysis I've determined that this issue is not related to v3.3g and is not a bug. The problem appears to stem from a conflict with Zone Alarm (firewall). After uninstalling Zone Alarm I do not receive the error message reported above.
I found that the following Zone Alarm files had changed on my machine a couple of days after I installed v3.3g in the Windows/system32 directory. I restored an image of my machine to the day before these updates and ImageMagick worked fine within Share.
vsconfig.xml
zpeng25.dll
vswmi.dll
vsxml.dll
zlcomm.dll
zlcommdb.dll
vsdata.dll
vsinit.dll
vsmonapi.dll
vspubapi.dll
vsutil.dll
My final test was done using ImageMagick 6.6.0 which I downloaded from their site when I was diagnosing this problem. I do suspect (as mentioned in the post above), but haven't confirmed, that the OOTB v3.3g ImageMagick files don't work in a Windows environment since I did see a different error message appear when I ran with the OOTB version.