@parkcityxj,
I am running some wp and wpmu installs on a GD hosting account without any problems. The initial configuration, however, was a bit confusing. It has been quite a while since I did this, so forgive my 'old-timers'.
In your Domain Manager for the target domain, you should have the following:
ARecord @ {yourIP}
ARecord * {yourIP}
Under Domain Management, you should create a sub-domain for each sub-domain you want. Point all sub-domains to the folder of the domain of your wpmu install.
In your .htaccess file, located in the folder of you wpmu install, make sure you have the following entries:
RewriteEngine On
RewriteBase /
...other wp stuff...
<IfModule mod_security.c>
<Files async-upload.php>
SecFilterEngine Off
SecFilterScanPOST Off
</Files>
</IfModule>
In your primary hosting domain root folder, make sure you have the following in the php5.ini file:
upload_max_filesize = 8M /* or 12, 16, etc. */
memory_limit = 64M /* or 128, etc. */
That's basically it for the GD config stuff.
You may want to remove/rename the wp config stuff to re-run the installer so that you can re-enter your db/site info.
Hope this helps.