The icaBar runs, by default if the user has administrator rights. Could be possible (for local accounts, not Domain ones) that a local-manually created account in both servers has admin rights in one and not in the other.
If the account is a domain one (not locally created):
1. Launch Poledit in each server and choose "open registry"
2. Double click "Local Computer" and expand the "System" key, and "Run"
3. The "Run" is checked by default and if you click in the word "Run" (right to the checkbox) a button will appear below "Items to run at startup - SHOW".
4. Click the button and in the "Value Name" you should see "IcaBar" and the Value should be "icabar.exe /adminonly".
Conclusion, if the user has no administrator rights and it shows up is because the /adminonly is missing. If the user has admin rights and the icabar doesn't launch, the "IcaBar icabar.exe /adminonly" is probably not there.