This error is reported because 0045H is autovector location populated by EZ-USB hardware. So firmware cannot populate any code there. This error can be neglected.
For more explanation and to know how to avoid Keil reporting this error refer this link from Keil: http://www.keil.com/support/docs/863.htm
To know more about USB Auto vectored Interrupts refer Page 4-15 of EZ-USB TRM.