Try/Catch in ColdFusion

Hi,
I'm a little new to Coldfusion so I could use a little help with catching errors.

I have a program the is invoked from an email link to activate an account.  It has a statement to decrypt a URL variable :

<CFSET account = decrypt(toString(toBinary(url.encrypted)),application.seed)>
<cfif account eq table.account>
  {do some updating}
</cfif

The problem is that if the user cuts/pastes only part of the encrypted URL, the CF decryption fails and goes to a general ColdFusion error screen.

I would like to catch this error and return my own page.

I've never worked with try/catch so could someone sketch the structure for me?

Thanks in advance,
hefterr