You can’t upgrade from 2008 directly to 2017.
You need to upgrade to the 2912 program first or you can call Intuit & they can upgrade the file for you.

Resolution for '2912 program issue: 'Just upgraded to qb 2017 pro from 2008 pro. Now unable to open file even after restoring from backup' available: Yes.

The 2912 program issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the 2912 program issue yourself by looking for a resolution described in the article. If it is a complex 2912 program issue or you are unable to solve the issue, you may contact us by clicking here or by using other 2912 program support options.

For more information about resolving issues related to 2912 program in Quickbooks/QBO or to get support for the issue 'Just upgraded to qb 2017 pro from 2008 pro. Now unable to open file even after restoring from backup', click the link below: