There is no inherent limitation on how "wide" your data should be to work within EG. Your first issue sounds like a problem that requires follow-up with tech support.
The second issue is probably due to volume and output format. 500 columns by 50 rows results in 25,000 table cells. If you are using the default output format of HTML, the resulting HTML result might be large and take a while to render. You can test this by setting your result options to use Text listing instead of HTML and see if the result appears faster.
I've used both more rows and more columns successfully (though I've never tried to print an entire dataset that is that big!). This note shows some ways to get more efficient throughput for large data in EG