I received an error message which states: Invalid Version found 220.127.116.11. Crystal Xcelsius expects version 18.104.22.168.
Does this mean that I cannot open my previous projects?
Yes, if you receive that message, then it means you won't have the possibility to open the previously created files because this is the way the software is working. It doesn't have compatibility with files created with previous versions. I would avoid using those files until you can get an official statement from the ones that created Xcelsius. You will either have to convert your files or install a previous version and export the content to another format that new version of Xcelsius can open.
The software's new name is SAP BusinessObjects Dashboards Community and you can obtain information about it from the following website: http://www.sap.com/community/topic/businessobjects-dashboards.html