A new password will be generated for you and sent to the E-Mail address associated with your account, all you have to do is enter your callsign.
NOTICE that GMX, ATT, T-Online, Web.de, sbcglobal, bellsouth, bigpond and swbell are rejecting all E-Mails sent by DXMAPS (Ask them why...). If you don't receve the E-Mail with your new password this is likely to be the reason. In that case contact the webmaster.