Below is my Interpretation of FII OI data Sheet for 01-Apr-12.
1. FII  bought  7189  Contracts of NF worth 192 cores OI also decreasing  by 10065 contracts.
 
2. As Nifty Futures was up by 17 points and OI has reduced by 100065 ,which basically means Long liquidation by FII. They are using the rise to liquidate there longs.
3. Nifty 
 closed above 20SMA@5291 which is bullish sign.Next important level 
comes to 5319 which is 50 SMA,Nifty just closed tad below this level.
 
4.
 I have been talking about the range of 5221-5370 NF based on Rollover 
data, look at today's high on NF it is at 5272 and it reacted decisively
 with 40 points quick fall.Litmus test failed at 5370. Fresh longs 
should be taken above 5372 NF only.