st: forvalues problem

[Morrison Hodges <hodge002@umn.edu>]

I have the following code:
----------------------------------
/*                  cdp.do

    Creating a cumulative distribution plot for use in PreFib analysis
    Created by MH on Friday, August 23, 2012
                                    */
version 12.1

capture log close
set more off

use prefib.dta, clear

label data "PreFib Data"

summarize grpa_jumpnmbr       /* to get the number of rows in 
grpa_jumpnmbr */
local nmbr r(N)             /* gets the number of rows in grpa_jumpnmbr */
sort grpa_jumpnmbr            /* sorts grpa_jumpnmbr from lowest to 
highest */
gen ptile = 0                /* new variable to place percentiles in */
gen dif = 1/`nmbr'            /* generates the percentile difference to 
be added to each row */
replace ptile in 1 = dif    /* lowest number is the lowest percentile */

forvalues i = 2/`nmbr' {

    local back = (ptile in (`i' - 1))
    replace ptile in `i' = back + dif

}

log close
---------------------------------------
I get a syntax error with this, but I don't know why. Thanks in advance 
for any help.

Morry Hodges
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