My custom cfx tag does implement com.allaire.cfx.CustomTag interface. Can someone help to understand why I'm getting this error?

I'm running this on cf8. The .java source file begins:

package com.argus.cfx;

import java.util.HashMap;
import java.util.Map;

import com.allaire.cfx.CustomTag;
import com.allaire.cfx.Query;
import com.allaire.cfx.Request;
import com.allaire.cfx.Response;
import com.argus.util.FileUtils;

public class PDFVersionReducer implements CustomTag {
    public void processRequest(Request request, Response response) throws Exception {
        String file = request.getAttribute("file");
        String version = request.getAttribute("version");
        String result = request.getAttribute("result");
        File f = new File(file);

as you can see, the file does implement CustomTag so I'm thinking that the error message may be a red herring...if it couldn't find the class I'd expect to get a class not found I'm thinking it may be something with my setup?
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cfmdevAuthor Commented:
Turns out this was a class path issue. Once I fixed that...the custom tag worked as expected...

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