If you are sure that php and sql version is not changed, try to rename your modules one by one via FTP to find out which module cause the problem. Do you have custom template ? rename it and try the xoops default theme. And check your logs for error (apache logs)
Hi , It is possible that your old host was using a older php and mysql then your current host. please check that first or try to disable/rename your .htaccess (if you have)
Maybe its handy to provide your xoops version and used modules