Hi Peter and welcome!
In my test with v8 Pro, your syntax for this formula is correct.
I know I'm stating the obvious with this one, but I would double check that you've included the colon : in the formula.
Also make sure that the field length and display width in your calculated field are large enough to properly capture and dislay the data required.
Let us know if you still need help with this.
Effective September 30, 2005 the upgrade path to v8 is only available to v7 users.
I would encourage you to [url="http://monarch.datawatch.com/monarch-pro.asp"]upgrade to v8[/url], Pro version if you have the need.
Thanks for the update.