This error is usually the result of a mismatch in regional settings. For example, the NetCommunity site may be set to Canada, but your regional settings are set to United States. To resolve, the regional settings on the workstation where the Raiser's Edge is accesed need to match the regional settings for NetCommunity.

If the Raiser's Edge is hosted by Blackbaud, update the Regional Settings for Citrix
If your organization hosts the Raiser's Edge, upgrade the regional settings on your workstation. The steps to do so will vary by your operating system. To find the steps, you can either ask your IT department or do a search, for example on Google, for "how to update regional settings."