Authorize.net error 103

I am getting the error 103 that means invalid credentials. I have checked and double checked and have the correct api credentials in place. I have tested it on a different shopping cart (non Webassist) and it connects fine. I'm thinking it may be the md5hash as I do have a 'specific' hash set in the Authorize.net control panel. I cannot find where to put it in Webassist. I realize I may be barking up the wrong tree and it may have nothing to do with the md5hash. Thanks for your help.

I'll need to troubleshoot directly, see the private message section.

See PM

See pm

on the confirm page, i had to update the code for the timestamp variable from:

<input id="x_fp_timestamp" name="x_fp_timestamp" type="hidden" value="<?php echo("<?php $WACalculatedHash = WA_CalculateHash(''.($WA_Authorize_Net_API_Credentials_Login_ID)  .'', ''.($WA_Authorize_Net_API_Credentials_Transaction_Key)  .'', ''.$sCart->GrandTotal()  .'', ''.AuthNet_RandomID()  .'', 'USD')?>
<?php echo $WACalculatedHash[1]; ?>"); ?>">

to:

<input id="x_fp_timestamp" name="x_fp_timestamp" type="hidden" value="<?php $WACalculatedHash = WA_CalculateHash(''.($WA_Authorize_Net_API_Credentials_Login_ID)  .'', ''.($WA_Authorize_Net_API_Credentials_Transaction_Key)  .'', ''.$sCart->GrandTotal()  .'', ''.AuthNet_RandomID()  .'', 'USD')?>
<?php echo $WACalculatedHash[1]; ?>"); ?>">

but now it is showing the following error:

<b>Fatal error</b>: Call to undefined function mhash() in <b>D:\PLESK\VHOSTS\redsneakers.net\office-furniture\WA_eCart\checkoutScripts\WA_simlib.php</b> on line <b>30</b><br />

the mhash funciton is one that is defined by php, you will need to contact the host to have them enable the mhash function