Hello, I would suggest contacting support@lunarpages.com for help with this issue.  From what I can tell from the forums here it doesn't look like that domain name is registered:

http://whois.domaintools.com/gnpcrescend.com

What kind of error are you getting? The Home Page you gave comes up fine for me. Have you tried refreshing the browser (clear the cache or force a reload of the page with Ctrl-F5). Does the error come up deeper into the site?

Did LP report doing any upgrades to your server recently? PHP or MySQL upgrade? With PHP, it's a common problem to have trouble when register global variables are turned off (LP seems to be turning them off on all the servers). The older versions of osC (pre RC1) depend on them, so you may need to turn them back on in your php.ini file. If MySQL was just upgraded to version 5, you'll get some "column not found" (1054) errors due to a change in precedence levels. It can be fixed by editing a few of the osC PHP source files.

OK, when I click on the shopping cart, I get a number of errors starting with

Warning: main(includes/languages/.php) [function.main]: failed to open stream: No such file or directory in /home/gnpcre2/public_html/store/includes/application_top.php on line 299

This appears to be the code lines

if (!tep_session_is_registered('language') || isset($HTTP_GET_VARS['language'])) {
      ...
    $language = $lng->language['directory'];
    $languages_id = $lng->language['id'];
  }

  // include the language translations
  require(DIR_WS_LANGUAGES . $language . '.php');

where $language isn't being set for some reason. Have you tried turning register globals on, to see if that makes any difference? If LP just turned off register globals on your server, that definitely will break osC if you're not already at 2.2 RC1 (the latest).