If you are very familiar with the following error message, here might be the quick fix you are looking for:

First of all you should try to optimize your virtual memory settings. During Export or Preview Xcelsius needs a lot of memory for conversion of Excel logic to ActionScript.

I recommend to set the virtual memory to a fixed value (no range) twice as large as windows recommends. The advantage of a pagefile with fixed size, is that the system does not have to dynamicly resize the file during runtime. As you can see below i set my pagefile to a fixed value of about 8GB.

Well this is just a Quick-Fix. For those, who like to go much deeper into the pagefile-topic and like to perform a professional pagefile optimization, i recommend reading the following article of "The Elder Geek":

http://www.theeldergeek.com/paging_file.htm