ZoneAlarm Security Suite Firewall randomly and prematurely terminates all file downloads greater than 80KB when it is the only firewall running.
There is no other 3rd party security software on the machine.
My computer runs Windows XP Pro with SP3, Internet Explorer 7 and ZASS v8.0.059.000.

All MS and ZA products are fully updated.
The Maxdata computer has Intel D915PBL motherboard, Intel X86 Family 15 Model 4 Stepping 1 ~3000MHz CPU and 512MB RAM.

All settings in ZASS and IE7 are default.
General broadband surfing and emailing are fine but whenever I attempt to download and save larger files, eg the 534KB GoogleEarthSetup.exe version update, the progress bar reaches download complete too quickly because in fact it has only downloaded a random amount between 20 and 80KB.
I have tried reducing the ZA Firewall Internet Zone setting from high to medium, emptied IE7 temporary file cache and even uninstalled and reinstalled ZASS.
In IE7 I have ensured that all cookies including 3rd party ones are allowed, and have temporarily disabled the phishing filter.
All to no avail.

I have found that downloads will only complete successfully if Windows Firewall is turned.
It makes no difference if ZA Firewall is simultaneously running (I know this is not recommended), but with both firewalls running the computer behaves normally in all other respects.
Windows Firewall is set to allow several Exceptions but the file download still completes even if I disallow them.

I also have a Lenovo 300 C200 laptop with identical OS, IE7 and ZASS software.
At first I was puzzled by the fact that this pc could download files greater than 80KB when I knew, or rather thought I knew, that its Windows Firewall was turned off because Disable Windows Firewall was checked in ZA Firewall s Advanced Settings.
Further investigation reveals however that the Lenovo startup process overrides the ZA setting and enables Windows Firewall.
Without realising it I had been running both firewalls simultaneously ever since installing ZASS.
Turning Windows Firewall off manually on the Lenovo makes it replicate the Maxdata s behaviour in every respect including the premature download termination.

Has anyone else experienced this behaviour or found a solution that does not involve having to have both firewalls running?

Operating System:Windows XP Pro
Software Version:8.0
Product Name:ZoneAlarm Internet Security Suite