can anybody see a problem with this function?

function doCode(fString, fOTag, fCTag, fROTag, fRCTag)
    fOTagPos = Instr(1, fString, fOTag, 1)
    fCTagPos = Instr(1, fString, fCTag, 1)
    while (fCTagPos > 0 and fOTagPos > 0)
        fString = replace(fString, fOTag, fROTag, 1, 1, 1)
        fString = replace(fString, fCTag, fRCTag, 1, 1, 1)
        fOTagPos = Instr(1, fString, fOTag, 1)
        fCTagPos = Instr(1, fString, fCTag, 1)
    wend
    doCode = fString
end function

Waht are you trying to acieve?
What exact error are you getting?
Exactly where does the error occur?

All that type of stuff will help others help you...

Wind is your friend
Matt

the function is meant to modifiy the rs("field") coming from database into html tags.
is used with another function
function formatstring(fString)
  fString = docode(fString, "", , "<b>", "</b>")
...
end function

on the page called as this

<%=formatstring(rs("field"))%>

the error is Type mistmatched

;;;the error is Type mistmatched
As I asked above, where is this error happening? Do you have 'show friendly http error turned off' if so this should give you a line number also.

Tricky to troubleshoot. EG what types of data are being passed in these variables:
fString, fOTag, fCTag, fROTag, fRCTag

IMO looks like a verbose way to generate some html. Perhaps there is a better way to get the result you are looking for. If you could elaborate on:
;;;the function is meant to modifiy the rs("field") coming from database into html tags.
What is your objective? Eg I am dealing with a RS that is a string data type, if the string = "fffffff" and the first char is a "f" then wrap it in the following html tags else...

Wind is your friend
Matt