You are not using the tags correctly. the {* and *} are tags to comment out sections. So that means that you commented out the words that you wanted to insert.
Change from this:
Code:
{* $Id: mail_header.tpl,v 1.2 2004/05/28 12:21:02 max Exp $ *}
<FONT size="2">
{* Thank you for visiting our store *}
{$lng.eml_mail_header_part1}
{$config.Company.company_name}
{* Please com again.*}
{$lng.eml_mail_header_part2}
</FONT>
to this:
Code:
{* $Id: mail_header.tpl,v 1.2 2004/05/28 12:21:02 max Exp $ *}
<FONT size="2">
Thank you for visiting our store
{*{$lng.eml_mail_header_part1}*}
{$config.Company.company_name}
Please com again.
{*{$lng.eml_mail_header_part2}*}
</FONT>
That comments out the two language variables {$lng.eml_mail_header_part1} and {$lng.eml_mail_header_part2}.
Alternatively, you could have also commented them out like this:
{*$lng.eml_mail_header_part2*}