(Adds details on nature of glitch)

JOHANNESBURG, April 23 (Reuters) - A database glitch delayed the start of trading on the Johannesburg Stock Exchange (JSE)

JSEJ.J for an hour on Wednesday, the latest in a string of errors that have hampered Africa's biggest bourse in recent years.

Trade on the $900 billion exchange did not start until 0800 GMT, rather than the usual opening time of 0700 GMT. Investors shrugged off the delay, however, with the benchmark Top-40 index

.JTOPI hitting another record high soon after the open.

The JSE said in a statement that the error was "related to a JSE database" and not the two-year-old Millennium Exchange trading platform that it had promised would put an end to its stability problems.

The bourse moved to the Millennium platform, which is developed by a unit of the London Stock Exchange Group LSE.L , in 2012 to increase trading speeds and in a bid to prevent the network errors that have disrupted trade in recent years.

The glitches have been an embarrassment for the JSE, which is looking to court more overseas investors and market itself as a gateway to Africa's growing capital markets.

In 2011 trade was halted for more than 30 minutes due to network problems. A similar issue stopped trade for more than six hours in 2010.

The JSE's shares were flat at 92 rand at 1216 GMT on Wednesday.

(Reporting by David Dolan; Editing by Stella Mapenzauswa and Pravin Char)

((david.dolan@thomsonreuters.com)(+27 11 775 3150)(Reuters Messaging: david.dolan@thomsonreuters.com@reuters.net))

Keywords: SAFRICA BOURSE/