does that happen when you start the client? sounds like an issue with inconsistency in the wallet file when it's generating out the transactions to fill the transactions tab.

i would recommend booting up the client using the '-rescan' option which will force a rescan of the blockchain to verify all the wallet transactions

if this does not work then you probably need to use a fresh wallet.dat and import the private keys into there which will rebuild the entire wallet. do you have the private keys for your wallet backed up? if so, simply run the 'importprivkey' command in debug console on a new wallet file otherwise you can use the 'importwallet' command to import private keys from a wallet file

you don't have the private keys and the importwallet fails or your old wallet.dat is encrypted, try opening the wallet using an old client (out of sync is fine), unlock the wallet if required and use the 'dumpprivkey' command on each of your addresses to get a private key which you can then use to 'importprivkey' in your new wallet