Problem using file inserttag with Form generator

I have a frontend Form Generator form in a protected members page.
To return a hidden value (pid) into the form i have made a php script (in the Templates folder) to get the value from a database query, and return it to the form via the file::filename.php insert tag.
This works fine, and shows up in the "view source" of the form,

Code:

---

<input type="hidden" name="pid" value="?18" />

---

and the pid value is also returned in the email that the form sends to me when it is posted

But the value will not go into the database.
The record is added,including all the other insert tags I use like user::firstname etc, but the pid value that is actually inserted into pid field is the sql default value of 0.
(I have tried also using the "file::filename.php" inserttag to update other fields, thinking it was something to do with pid, but still no go.)
I can't figure why this isn't working. I would have thought that since both the source and the email show the value, then it would work.
Any insights anyone?

Hi ramjet,
did you solve the problem? Else: did you try a different field name (i.e. not "pid")?


cheers
Antipitch

Hi Antipitch,
I've worked around it another way.
But as far as I can tell it is not possible to use the file:: insert tag within a form field and have it go into the database.
It wasn't just "pid" but any variable i tried.
(as I say... the returned value posts via email alright and also shows up in the page source, but doesn't submit into the database).
One of those mysteries, like the Loch Ness Monster.