The main reason you have not matched table 11.10 on page 183 of the Nepal 2011 report is that you did not apply all the restrictions given in the footnote to the table. You need to remove the cases with v438 coded in the 9000's; the women who are pregnant; and the women with a birth in the preceding two months. You missed the third restriction, which requires looking at v008-b3_01. Here, v008 is the cmc of interview and b3_01 is the cmc of the most recent birth. You exclude the case if that difference is 0 or 1. I will put my modification of your code below and then the tabulation that corresponds to the bottom row of table 11.10.

gen bmi=v445/100 
gen bmic=1 if bmi<18.5
replace bmic=2 if bmi>=18.5 & bmi<25
replace bmic=3 if bmi>=25 & bmi<30
replace bmic=4 if bmi>=30 & bmi<50
label define bmic 1"Underweight" 2"Normal" 3"Overweight" 4"Obese"
label values bmic bmic
gen ht_flag=0
replace ht_flag=1 if v438>9000
gen preg_flag=0
replace preg_flag=1 if v213==1
gen months_since_last_birth=v008-b3_01
gen recent_birth_flag=0
replace recent_birth_flag=1 if months_since_last_birth<=1
tab bmic if ht_flag==0 & preg_flag==0 & recent_birth_flag==0 [iweight=v005/1000000]

       bmic |      Freq.     Percent        Cum.
------------+-----------------------------------
Underweight | 1,055.0565       18.19       18.19
     Normal | 3,963.9914       68.35       86.54
Overweight | 650.396456       11.21       97.76
      Obese | 130.142492        2.24      100.00
------------+-----------------------------------
      Total | 5,799.5868      100.00

Your Stata code should work. The discrepancy in the number of cases is small and may be due to the difference between de facto and de jure residence (see hv102 and hv103 in the household file, v134 in the IR file). Or it could be the difference between the women who are in the PR file and those who are in the IR file. These numbers may differ slightly. Please look into those possibilities. If you still can't get a match, please tell us.