A new patch has recently come out, with some bug fixes, as well as new abilities and items for characters to play with. The following list of changes comes from the official patch page.

Two new items added! A Gold Ioun stone and a Silver Ioun stone have been added into Throne of Bhaal.
Adds to the Adventure Mart in Shadows of Amn the merchant Deidre and the special items from the Collector's Edition of SoA.
Fixes a stutter bug experienced by some players that caused the game to pause momentarily every few seconds while playing.
Fixes the NPC "X appears busy" bug associated with Win2K and WinXP
Fixes the problem where WinDoctor or other registry checking/cleaning programs would erase the BG2: Throne of Bhaal registry entry
Fixes the incorrect calculation of the assassin backstab modifier when importing an assassin character from Shadows of Amn to Throne of Bhaal
Fixes the party-splitting bug where players would make the in-game transition from the end of Shadows of Amn directly into the start of Throne of Bhaal and have some characters left behind in Shadows of Amn
At level 20, the Jester bardsong ability also gains stun and slow in addition to confusion.
New keymap file fixes the problem where certain keys could not be assigned. Some of these keys are now no longer assignable from the config program due to localization reasons (though can be assigned manually - read on). This new keymap file will replace your current keymap.ini file which means that you will lose all of the key mappings if you have made any. Your current keymap.ini will be renamed to keymap.ini.ToBpatch.backup when the patch is run. To restore all your key mappings after running the patch, copy the entire section from keymap.ini.ToBpatch.backup and replace the one in keymap.ini for the following sections:
[Keymap Page]
[Keymap Actions]
[Keymap Miscellaneous]
[Keymap Quick Slots]
[Keymap Priest Spells]
[Keymap Wizard Spells]
[Keymap High Level Abilities]
High level Sorcerer characters who already have 10th level spells from SoA, will no longer permanently lose them when reselecting their spells upon transition/import into ToB. In fact, they need no longer need to reselect any of their spells. Lower level sorcerers (below 2.95 million XP) will still have to reselect their spells, but this gives them the chance to choose different spells to use in ToB.
The icon and the kit description for the Blade now have identical name for the same ability.
Fixes the bug where dialogues for unfinished quests from SoA would show up in ToB.
Fixes the bug where Greater Restoration scrolls would appear as Lesser Restoration in the Quick-Item slot.
Fixes bug where a second drow woodcutter was duplicated both inside and outside the cabin if he initially followed you inside.
Fixes rare bug where the game would lock in cutscene mode if the Spectator is attacked before the cutscene involving Captain Egeissag initiates.
Fixes the problem where Wild Mages created in SoA would not get the opportunity to learn Improved Chaos Shield. The spell now automatically appears in the 7th level page of the spellbook at the start of SoA.
Wild Mages are now viewable in the Character Viewer program.
Fixes bug where stackable items (eg. potions) would not stack when buying them at the store, hence filling up your inventory slots with one item each. The items will stack correctly now when buying them in the store screen.
Fighter/Druids can now put two proficiency points in Two-handed and Two-weapon styles.
Fixes the bug where the Rest Until Healed option wouldn't work in all cases.
Fixes a bug where dual-classed characters lose their inherent abilities.
Fixes bug where Carras the smuggler would not offer special items after fighting the monks.
Fixes bug where monsters were duplicated when transitioning across areas.
Fixes bug where drow scimitars would kill bards instantly.
Fixes the rare bug where players could enter into Balthazar's monastery through the locked door in the Amkethran graveyard without using the key.
Fixes rare bug where players could not progress to the 2nd level of Watcher's Keep after killing all the statues.
Fixes the problem in the Config program where changing the Graphic slider would enable the 3D acceleration setting.
As a clarification, Multi and dual class characters gain their first high level ability at the equivalent XP mark as a single class character. Everybody gets their first high level ability at approx 3 million xp, give or take a few thousand. This was done to allow multi and dual class characters to enjoy the benefits of high level abilities before the end of the game.
Fixes the Jaheira Romance in Shadows of Amn (special thanks to Kevin Dorner and Michael Kurela!)
Multiplayer Specific fixes:

Fixes the multiplayer bug where Sarevok keeps repeating his first line of dialogue after the player makes the in-game transition from Shadows of Amn to Throne of Bhaal.
Fixes bug in multiplayer where SoA save games were displayed on the ToB multiplayer or single player Load Screens after quitting from a ToB multiplayer game.
Fixes the multiplayer bug where a client would quit a SoA game and host a ToB game, when in fact they would be hosting a SoA game.
Fixes the multiplayer bug where simulacrums were allowed to join your party. They can no longer join your party.
Fixes a rare multiplayer bug where setting a snare while saving would crash the game.

To get this patch, visit the Bioware patch page. Happy gaming!

• Official Bioware Site

• Throne of Bhaal patch
• Throne of Bhaal review