explaintions about 500 Internal Server Error

all info and explanations for this error would be much appreciated. thought we had all bases covered but still see this sometimes from wp/admin while working and while browsing as well
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Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, webmaster@voiceofguyana.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.
Apache/1.3.37 Server at http://www.voiceofguyana.com Port 80