Legacy Cumulus 1 release 1.9.4 (build 1099) - 28 November 2014
(a patch is available for 1.9.4 build 1099 that extends the date range of drop-down menus to 2030)
Download the Software (Cumulus MX / Cumulus 1 and other related items) from the Wiki
I have been currently receiving a pop up box stating "An error has occurred in Culumus, a bug report has been created in the Cumulus folder. it gives two options to either close application or restart.
It's crashing in Microsoft code, in msvcrt.dll. Unfortunately the component which produces this output has then had some kind of error, which means that it's not able to tell me what part of Cumulus is involved. Cumulus doesn't use msvcrt.dll directly (it's the Visual C run time library, and Cumulus isn't written in C) so I can't even guess at what might be going on.
I haven't seen any reports of this error from anyone else, so it appears to be something specific to your system, and I'm afraid I have no suggestions as to what the cause or solution might be. The latest occurrence was a week ago, so perhaps the problem might not happen again.
msvcrt.dll is part of the C++ / C# Visual C distributable library that a lot of programs install as part of the software install.
I suggest you get a copy of the latest version from the Microsoft download site and try installing it. Or if you remember installing a piece of software that said it was installing the C++ RunTime Library uninstall that software to see if it cures the problem. It looks to me like something has installed an incompatible version of the .dll.