How Do I Fix: "Safe mode: Warning: Displayed transactions may not be correct!" While trying to retrieve the private key from satoshi bitcoin client i'm getting this error code:  

Safe mode: Warning: Displayed transactions may not be correct! You may need to upgrade, or other nodes may need to upgrade. (code -2)

Does anyone know how to fix this?

It is QT VERSION 4.8.2 &amp; v0.7.2-beta in the lower right hand corner it says it is catching up but has not added any blocks for a really, really, really, long time, it sitting on 90.13% . What else do you need to know?

I am Technically inept so I need to be clear so I dont screw up. I NEED THE PRIVATE KEYS for 2 ADDRESSES generated by this bitcoin-qt, when I type in dumpprivkey address I get the above error message. Will upgrading cause a conflict?  What is the proper way to upgrade as I dont see that as an option?
Typically, this is caused by a corrupted block chain database - it causes your client to consider the real chain invalid, and try to find another one. Since the real chain remains the longest obviously, it shows this warning, as it notices its opinion differs from the rest of the network.

The solution is deleting blkindex.dat/blk000?.dat and let redownload the chain. In case you're running 0.8 (if not, upgrade), you can just use -reindex to rebuild the database (no downloading necessary in that case).