In the book I have written, one of my characters recites a portion of the Dhammapada. How do I avoid violating copyright laws? The quote is from a translation on a website, but I can't find any contact info to contact either the author of the page, or the translator.
There are a few basic copyright rules, but it is a significant grey area when it comes to fiction. In the US, information in the "public domain" is always legal to draw from. This begins 90 years after print publication (1927). However, this does not take into account retranslations coming after 1927.
Facts are always allowed for reproduction as long as they're verifiable facts. Names, places, dates, etc., are always ok.
Reporting actions are ok, but attributing those actions to a particular motive begins to open you up to risk.
Song lyrics are particularly tricky, or so I've been told.
However, commercial publishing companies have their own attorneys to deal with such things. You should finish your book, a mammoth task, and then worry about the problems.
In the end, if your book is fictional, it wouldn't be too hard to alter the exact translation and still get your point across. This may still open you up to some risk, so if it's really a problem, and you expect to make at least a few thousand dollars, you can always talk to an attorney.
If you have the name of the book and the year and probably also the place of publication (country or city), you can probably find the publisher. Wikipedia has a number of sources about the Dhammapada.
Indeed the copyright laws last a couple of decades since the last publication or even with music until 75 years after death of the musician when it is not inherited by family or other persons. This depends on the country though. I just gave an example about the copyright law in The Netherlands.
What works is to mail the publisher of the book you used the quote from - the website should have mentioned it otherwise they do not mention their source correctly. But as I mentioned: you should mail the publisher if you can have permission to use the quote in your fiction book. You can even suggest to otherwise use their name of source in a footnote or something. You need written permission to not be sued for violation of the copyright.
The logical answer: Copyright is valid for 70 years . . . anything allegedly said by "Buddha" is probably out of copyright.
Anybody suing for copyright of Buddha's words is claiming the words were not Buddha's but theirs, the downside of the claim is that they would be admitting their own fraudulent activity.
In simple terms: if you cannot be sued for using a bible quote, why would the rules be different for another religion.