How do I syntactically validate a variable name

[fusionaire]

this is the error message that I am getting:<br><br>Error Diagnostic Information<br>Parameter 1 of function IsDefined which is now &quot;209.195.159.132&quot; must be a syntactically valid variable name<br><br>The error occurred while evaluating the expression: <br><br><br>&nbsp;IsDefined (get_ip.ip) <br><br><br><br><br>The error occurred while processing an element with a general identifier of (CFIF), occupying document position (24:1) to (24:29<br><br><br>what can I do to make it valid?

 

[iza]

IsDefined (&quot;get_ip.ip&quot <br>

 

[fusionaire]

Thanks again, Iza