You are having an issue with a trunk between two switches. Examining the following figure, what can you conclude?

On Switch A, DTP is turned on and the encapsulation is set to 802.1Q. However, on Switch B, DTP is turned off and ISL encapsulation is manually set. Switch B will need to have 802.1Q configured in order to have trunking complete. Both Switch A and Switch B have their interfaces set to trunk mode already. DTP is running on Switch A, since the mode is set to auto. All VLANs do not need to be allowed first for trunking to happen.