What error 1707 stands for? I get this error, in following situation as below

1. I used compound index (.cdx) files and Free tables.
2. In DOS environment I delete all .cdx files of all tables.
3. In my application (.exe) when I run some code similar to the code below,

fn='abc.dbf' && gets assigned in run time
Sele b
use (fn) excl alia indfile <- I get erro at this attempt to use

I get error at this 'use' command
4. When give same command at .(Dot prompt) it works fine.

Can any one help me out please?