I see... it appears the DMXZone Extension Manager doesn't properly add the formats to the formats.xml file, and our files aren't set up to self-install.
I can update them so that they will install using the method you tried without error in a future version... for now you will have to edit your xml file directly.
Go to your users configuration folder and find the file:
Configuration/ServerFormats/PHP_MySQL/Formats.xml
add this code:
<menu id="EncFormatSecurityAssist_PHP" name="SecurityAssist">
<format title="Encryption - Crypt" file="WACryptEncryption" expression="<\?\s*php\s*echo\s*WA_CryptEncryption\([^\r\n]*\);?\s*\?>" func="WA_CryptEncryption" id="WACryptEncryption_PHP" />
<format title="Decryption - Hash" file="WAHashDecryption" expression="<\?\s*php\s*echo\s*WA_HashDecryption\([^\r\n]*\);?\s*\?>" func="WA_HashDecryption" id="WAHashDecryption_PHP" />
<format title="Encryption - Hash" file="WAHashEncryption" expression="<\?\s*php\s*echo\s*WA_HashEncryption\([^\r\n]*\);?\s*\?>" func="WA_HashEncryption" id="WAHashEncryption_PHP" />
<format title="Encryption - MD5" file="WAMD5Encryption" expression="<\?\s*php\s*echo\s*WA_MD5Encryption\([^\r\n]*\);?\s*\?>" func="WA_MD5Encryption" id="WAMD5Encryption_PHP" />
<format title="Decryption - RIJNDAEL" file="WARIJNDAELDecryption" expression="<\?\s*php\s*echo\s*WA_RIJNDAELDecryption\([^\r\n]*\);?\s*\?>" func="WA_RIJNDAELDecryption" id="WARIJNDAELDecryption_PHP" />
<format title="Encryption - RIJNDAEL" file="WARIJNDAELEncryption" expression="<\?\s*php\s*echo\s*WA_RIJNDAELEncryption\([^\r\n]*\);?\s*\?>" func="WA_RIJNDAELEncryption" id="WARIJNDAELEncryption_PHP" />
<format title="Encryption - SHA1" file="WASHA1Encryption" expression="<\?\s*php\s*echo\s*WA_SHA1Encryption\([^\r\n]*\);?\s*\?>" func="WA_SHA1Encryption" id="WASHA1Encryption_PHP" />
</menu>
That will add the formats you need to your format list.