Changes to the tcl files in the www/ folder will be considered automatically when reloading the page, whereas you have to explicitely mark the tcl files in the tcl/ folder as "watched" when you want your changes to take effect without a server restart. To mark files as watched go to /acs-admin/apm - if you have already modified some files then this page will offer to reload the affected package and after that to mark the changed files as watched. Otherwise you can go to the package via the package list and mark the files as watched that you plan to change. The same needs to be done for *.xql files (also below www/) if you are using them.
To debug you can also do
tail -f /usr/local/aolserver/yourserver-error.log | grep UNIQUESTRING