First I wanted to clarify you mean viewing/editing the responses on the "View Response" tab in the FormsCentral web site while signed in right?
Do you know if the Macbook is an "Intel" (Mactel) or "PowerPC" based mac? If it is PowerPC the Flash support is limited and we do not support FormsCentral on PowerPC, if it is an Intel based mac then the OS 10.5.x is still not supported but I would expect it should work with the latest browser and Flash Player. Has your college tried alternate web browser such as Google Chrome or Firefox?
Regarding the iPad that would not work by default for viewing/editig responses in FormsCentral as the iPad does not support Flash, there are 3rd party apps you can download to make it work, but it is not something we explicitely support.