This hasn't happened to anyone else. Probably some other plugin is causing problems.
Try this simple code:
PHP Code:
#include <amxmodx>
public plugin_init()
{
register_clcmd("say /flags", "change")
}
public change(id)
{
set_user_flags(id, read_flags("abcdei"))
client_print(id, print_chat, "changed flags")
return PLUGIN_HANDLED
}
Type /flags in the chat and see if your flags changed.