Searching for a "reserved error" message
So you've got one of those dreaded reserved error messages. "Reserved error (-9999): there is no message for this error." But how to attempt to troubleshoot this message? You're not getting any hits.
The most important thing is to remove the - (minus sign) in front of the error number. Otherwise the search engines assume you don't want any hits with that number in the returned links.
Now search at your favourite search engine and see if you get any hits in the first page or two that look somewhat like a resource web page. Use syntax like "reserved error" 1517. Now note that I have a page on 1517 so it will be the first hit. That page is useful. (Or so I like to think.)
But what about all the other hits? With the exception of Utter Access and the Access World all those other pages are useless copies of the Microsoft and Usenet NNTP newsgroups. I say useless because they all duplicate each others data and exist only to get money from Google advertising. In my not so humble opinion Google should not allow them to sell ads but I doubt Google listens to me.
In which case if you are searching for an answer visit Google, click on More and choose Groups. Now do your search here.
Unfortunately Google broke the Advanced Groups Search a few months ago which allowed you to limit your search to the microsoft.public.access.* and comp.databases.ms-access newsgroups. I mean you can't So I'd suggest adding the word access to your search.
Finally if you want to ask a question I'd suggest the Microsoft Office Online Access Database General Questions forum or either of the two above mentioned online forums.