this should do it:
Cannot Change Temporary Internet Files Cache Size
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The information in this article applies to:
Microsoft Windows 98
Microsoft Internet Explorer for Windows 95
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SYMPTOMS
The amount of disk space Internet Explorer uses for temporary Internet files may be set to 0 (zero) percent, and you may be unable to specify a different setting. In Internet Explorer 5, if you try to change the settings, you may receive the following error message:
Enter a number between 0 and 1 to indicate size of disk space for...
CAUSE
This behavior can occur if the History, Cookies, or Temporary Internet Files folder is damaged, or if a damaged file exists in one of these folders.
RESOLUTION
To resolve this behavior, follow these steps:
Click Start, click Shut Down, click Restart In MS-DOS Mode, and then click OK.
At the command prompt, type the following commands, pressing ENTER after each command, and pressing Y if you are prompted to confirm folder deletion:
cd\windows
smartdrv
deltree cookies
deltree history
deltree tempor~1
exit
NOTE : If you have a cookie that stores a password for a particular Web site, copy the contents of the Cookies folder to a new folder before deleting the Cookies folder. To do so, type the following commands at the command prompt, pressing ENTER after each command
md <folder>
copy c:\windows\cookies\*.* c:\windows\<new folder>
where <folder> is the folder to which you want to copy the contents of the Cookies folder.
Restart your computer.
Click Start, point to Programs, point to Internet Explorer, and then click Internet Explorer.
On the View menu, click Internet Options.
On the General tab, click Settings.
Move the "Amount of disk space to use" slider to the setting you want, click OK, and then click OK again.
reghakr