Found a Known Bugs List entry with similarities thought it reports issues with Instant Web Publishing and FileMaker 12.
Does it look like the same issue to you?
For More Information see: Contents streaming to internet is impossible over IWP
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip
Yes this is the same issue but I am using Filemaker 13. I hope that they fixed that issue. It look like they didn't loll
Thanks for the reply. If someone found any solution. Let me know