Let ( [ ~isWindows = Abs ( Get ( SystemPlatform ) ) = 2 ; ~hostName = Case ( ~isWindows ; "$" ; GetAsURLEncoded ( "$" ) ) ; ~fileName = Case ( ~isWindows ; Get ( FileName ) ; GetAsURLEncoded ( Get ( FileName ) ) ) ] ; "fmp://" & ~hostName & "/" & ~fileName )
Which version of 13 where you running?
There was a small change (or addition) in the 13v2 update. Here's a link to an article that sums that up.
Another thing is if you two instances of FileMaker it's hard to determine which of the two the call back wil open !
I am using FM 14. Database is hosted in a FM 14 Server
We had this problem on several of our client machines running FM Pro. Our problem was that FM 14 was installed before FM 13 was uninstalled. After 14 had been installed they went back and uninstalled 13 which broke the fmp URL for that machine. Rerunning the 14 install to repair the installation fixed the problem.
I am using FMP Adv 14 to access the hosted database. I did what you have suggested. Now when I click into the webviewer, it opens a new copy of FMPro. So I get 2 copies of FMP running on top of each other. Any suggestion how to resolve this ? Thank you.
Enter Find Mode 
Set Field [ TABLE::UUID ; $uuid ]
Perform Find 
As rrrichie already commented, you can use only one copy (version, edition) of FileMaker product for fmp: protocol handler.
Choose Adv or Pro which to use, and edit registry
or use installer of chosen program and repair it as clind wrote.
If you write your own protocol handler, you can run any FM selecting in it.
I removed the FM Pro from my machine, everything works fine.
Thank you so much for all your help
I think your test didn't run from webviewer.
This code succeeded on FM14 + Windows7
"data:text/html,<input type='button' onClick='location.href=\"fmp://%24/" & Get(FileName) & "?script=setf¶m=\"+\"value\"'>"
It's being tested only in Windows 8.1, but it may be the version of the OS and the one which depends on the version of Internet Explorer.
How shall I ...?