Forgive about the broken english.
I want you try follow the next steps:
1 - Point your web browser to the url: http://200.186.180.82:5000/SIA/RW/login.php
2 - Login using Coltro/TESTE
3 - Select 1 or 2 or 3 or 4 or 5 records
4 - Click "Exportação selecionada" button (Export selected)
5 - See the error message from PHP (mssql_query(): message: Error converting data type varchar to float. (severity 16))
After this, select 6 or more records and... the error message disappear... and the data are exported...
I never see this before.
Thanks in advance.