Boot with the Configuration Assistant diskette so you can review the resource usage.
Select View/Edit Devices from the Device Tasks menu, and review the list of devices to see how many IRQs are being used.
There are 16 IRQs, from 0-15. Several IRQs are already assigned. For example, IRQ 3 is reserved for the second serial port, COM2.
If your system has a COM2 port but it is not being used, delete the port to leave the IRQ resource free for a PC Card.
Boot the Solaris software.