I use the same package, can you post your code?

Maybe the problem is not in the laravel package, but in the program you are opening the file with. Try changing the file extension: .xls, .xlsx, .csv.
I have MS Excel 2007. Whatever I download from the internet. If I try to open it in from the browser I get some errors. I have to go to the Downloads folder and open it there.
Hope this helps.

Why do that, just sql dump from your host to your dev computer, then restore from sql dump, then open in ms access or excel. Of course you have to setup your odbc datasource. I use SQLlyog. I can do beautiful grouping reports like this. Once opened in access, I simply run report wizard. Only drawback is the small amount of time to down dump and restore from dump. A whole 2 to 4 minutes.

Have not used this yet.. but I will be this week. Excel can open CSV files and it may be easier to use this library: http://csv.thephpleague.com. The documentation is great too.

i think a csv file is your best choice here because you're not creating any excel specific data on the file. Your exported data is just a table ? csv files can be imported in to multiple applications and is easier to generate.