Never done an upgrade to 4.5, but a few of the posts in here suggest first upgrading to patch 7 for ePO 4, they trying the upgrade to 4.5p3.
Maybe give that a try first?
BTW- I have moved your post to the ePO forum for better attention.
Let me know any error pop installing ePO 4.5.
Use simple password for ePO authntication (without special characters) and atleast 10 digit.
Make sure windows login user have admin access. before starting installation make sure and stop any server tasks running.