If you're getting this message when logging into Acctivate, we've got some information on how best to deal with this issue here.
UPDATE: We have discovered that installing the 64-bit version of the Microsoft Access Database Engine does not resolve this problem with Office 2013. Microsoft still recommends the 32-bit edition of Office when using third-party 32-bit applications, such as Acctivate. Furthermore, we have been unable to find a workaround to send email through Outlook 2013 64-bit.
Acctivate installs the Microsoft Access Database Engine 2010 Redistributable component on each workstation and the server. It is the component required to import data from Microsoft Excel files. The 32-bit version of this component is included with the Acctivate software. The 32-bit version is compatible with 32-bit Microsoft Office running on 64-bit Windows. However, it is not compatible with Microsoft Office 64-bit editions.
You may continually receive the following message each time Acctivate is opened:
Updating Microsoft Excel Connectivity
Acctivate will then attempt to install the 32-bit version of the component, which may fail with the following error.
You cannot install the 32-bit version of Microsoft Access Database Engine 2010 because you currently have 64-bit Office products installed. If you want to install 32-bit Microsoft Access Database Engine 2010, you will first need to remove the 64-bit installation of Office products. After uninstalling the following product(s), rerun setup in order to install 32-bit version of Microsoft Access Database Engine: 2010: Microsoft Office Professional Plus 2010
You may need to download and install the 64-bit version of the Microsoft Access Database Engine from Microsoft.
AccessDatabaseEngine_x64.exe is available at https://www.microsoft.com/en-us/download/details.aspx?id=39358