So you've got your LightSpeed web store all setup and then BAM the order downloader won't complete successfully. You're probably about ready to give up at this point but wait, it might not be as hard to solve as you think. Here's some common reasons this might occur:
1) Products sold on the order no longer exist in LightSpeed (or the product code has changed). If this is the case, your best bet is to manually find the order in the MySQL database through PHPMyAdmin or a similar interface. Once found, you should manually add the order to your LightSpeed Point of Sale. Once it is added, delete the entire line entry of that order through PHPMyAdmin
2) The Web Order number (WO-) has already been download.
Reason 2) usually occurs in situations where several Web Stores have been tested with the same LightSpeed instance. Even if the order has been deleted from LightSpeed, the WO number is stored internally, preventing it from coming down again.
The way to rectify this is to go to Admin Panel > Store Settings > Localization and change the Next Order Id to something higher than has already been used, e.g. 40000.
If you need the orders already placed to download, then you will need to edit the MySQL database directly. The WO number is stored in the 'xlsws_cart table' under the 'id_str' field.
3) There is a third reason the downloader might cease to function, and that has to do with your mail settings of all sorts. Yep, for some reason if your Mail Server settings in LightSpeed fail to send mail, then the downloader will not correctly. Fixing the mail issue, with ultimately fix the download issue. We will be writing a tutorial soon on fixing the ever so common Mail Server settings.