Give more details about your environment and about what exactly are you doing!
Are you saying that it worked before upgrade to Chrome 25? What Chrome version it was then?
What operating system do you have?
Do you have administrative rights, or is your Windows user account restricted?
What's your Chrome setup? Is it installed normally (i.e. into Program Files), or is it perhaps a non-admin installation (i.e. in C:\Users\<username>\AppData\Local\Google\Chrome\Application)?
Were both programs (Chrome and Sticky) installed under the same Windows user account, or was maybe each application installed under different account?
Are there perhaps some instances of CHROME.EXE still running when you try to install the plugin? (you can see it in Windows Task Manager)