Dropbox recently "banned" the public folder we were using to distribute Analytic Technologies materials. Messages to users said we had exceeded bandwidth regulations. But on further inquiry, Dropbox said it was because we were "hosting malware". So as a first step we have deleted all files from the Dropbox location and started the process of finding new homes for main files. More on the way. If there is something you are missing, please send an email to steve at analytictech.com.
Interestingly, many users in recent years had reported that their Norton anti-malware software was flagging the ucinet setup file stored on Dropbox as malware. But when we would send the user the same file via other means (e.g., YouSendIt), Norton had no problems. We don't know what the deal is. We know there are a few news reports about Dropbox having problems with hackers using Dropbox accounts to spread malware. Maybe when Norton sees an installation file like ucinetsetup.exe on a Dropbox public folder, it becomes automatically suspicious and warns the user.
In any case, we will have to move away from using Dropbox to distribute AnalyticTech materials. Inconvenient, but one benefit is that it will make things easier for Chinese users. Most mainland Chinese have been unable to access Dropbox files since 2010. (Ironically, though, it is apparently Chinese hackers that have been abusing Dropbox. This is like the plot of an opera.)