My wife uses Gmail and has no problems accessing it at work or in our home (with either of our wireless laptops).
She has LOTS of trouble accessing it from our desktop in our home.
The only obvious difference in these computers is that the desktop has ZA Security suite 6.5.7.
I have Googled this issue and see greatly differing opinions about it.
This problem happens with both Netscape Navigator and Firefox (I don't use IE).

Operating System:Windows XP Home Edition
Software Version:6.5
Product Name:ZoneAlarm Pro