iMacros help

I was working on a macro to guess this particular code:
CowBoyBeebopXvj5ks21o73kdp4if9md5jp47???? (number, letter, letter, number)

The macro is done in imacro.
For my macro I have a file in datasources folder called input.txt. It has a copy of every possible combination, like this:
[iOpus]
name0=0
name1=0aa0
name2=0ab0
name3=0ac0

My code is:
SET !DATASOURCE input.txt
SET !VAR1 CowBoyBeebopXvj5ks21o73kdp4if9md5jp47{{name!LOOP}}
TAG POS=1 TYPE=INPUT:TEXT FORM=NAME:regf ATTR=ID:register_username CONTENT={{!VAR1}}
TAG POS=1 TYPE=INPUT:SUBMIT FORM=ID:regf ATTR=NAME:Submit&&VALUE:I<SP>agree<SP>-<SP>continue<SP>sign<SP>
;up
wait seconds=1

However the string it actually inputs is: CowBoyBeebopXvj5ks21o73kdp4if9md5jp47__undefined__

Question is:  How do I get it to put out the string as you may have guessed I want it being output like?

>>12
what browser are you using? from the documentation it appears as though this functionality is only supported in the IE version.