if your serial number is for cs4 master collection, you must install (some or all of) cs4 master collection. you can't use your serial number with cs4 illustrator.
Downloads available:
- Suites and Programs: CC 2014 | CC | CS6 | CS5.5 | CS5 | CS4 | CS3
- Acrobat: XI, X | 9,8 | 9 standard
- Premiere Elements: 12 | 11, 10 | 9, 8, 7
- Photoshop Elements: 12 | 11, 10 | 9,8,7
- Lightroom: 5.5 (win),5.5 (mac) | 5.4 (win), 5.4 (mac) | 5 | 4 | 3
- Captivate: 8 | 7 | 6 | 5
- Contribute: CS5 | CS4, CS3
Download and installation help for Adobe links
Download and installation help for Prodesigntools links are listed on most linked pages. They are critical; especially steps 1, 2 and 3. If you click a link that does not have those steps listed, open a second window using the Lightroom 3 link to see those 'Important Instructions'.