Dow Reels on Procter & Gamble Warning and Oil, Rate Fears.(Knight Ridder/Tribune Business News)

Mar. 8--A vulnerable Dow Jones industrial average lost nearly 4 percent of its value yesterday after a warning of lower profits by Procter & Gamble Co. fed into investors' fears that rising oil prices and interest rates would slow the economy.

The 374.47-point decline was the Dow's fourth-biggest drop in one day and pushed the index to its lowest closing since March 31, 1999. The Dow finished the day at 9796.03.

The seemingly invulnerable Nasdaq Composite index, which had soared more than 100 points to just over 5000 in the morning, eventually gave in to the Dow's downward pull. The Nasdaq began to fall after nervous investors in technology stocks cashed in some of their enormous profits. The index fell…