I have also just installed FrontAccounting on my webhosting service and have the same issue. The data is written to the database but the old values are stored in cache and will not display the new values in the web browser.
My database is accessed through phpMyAdmin but the database was created using MySQL Databases in cPanel. The privileges are also set through here and this is set to "All Priveleges" although there is no mention of the FLUSH privilege.
I have also updated .htaccess to include the following as this was mentioned in another post -
<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>
Any assistance you can give would be greatly appreciated as I really like the look of the software and am very keen to try it out.