Unable to deploy VB CRUFL function dll

THE EXACT MESSAGE RECEIVED when trying to run Crystal Report from website.

The Visual Basic UFL that implements this function is missing (or U2lcom.dll is missing). Error in File C:\CrystalReportsTempFolder\{8E35F0A6-2BC5-4013-81C0-9A4758B56493}.rpt: Error in formula <test>. 'formula = DisplayAs ("D", {company_tbl.reporting_id}, {company_tbl.employee_id_format}, {hr_master.employee_id}, {hr_master.soc_sec_no})' The Visual Basic UFL that implements this function is missing (or U2lcom.dll is missing).

/repaymedev/reports/AlwaysIncludeBegin.asp, line 28

THE line where the error occur is:

Set Session("oClientDoc") = objFactory.CreateObject("CrystalClientDoc.ReportClientDocument")
Session("oClientDoc").Open path & reportName     <+++ error line

Background:
the UFL functions was developed in VB6.
Crystal Report is v9.
The report was test run in Crystal Report with no error.  Able to see the report.

Error condition:
When the report is pushed to the website, this error occurs.  The is a mature website with other report using CRUFL successfully.  

Any help/suggestion welcome