I just installed Windows 98 SE and Windows automatically recognized and installed the necessary drivers for the "AMD PCNET Family Ethernet Adapter (PCI-ISA)". So if for whatever reason you can't select the correct driver from what's included in Windows then either the V4.51.zip or AMD_PCnet_family_VMware_nic_V4.51.zip from the links work. During the install one is prompted twice to "Please insert the disk labeled 'AMD Driver Disk 1', and then click OK." and you just need to point it back to that folder and it will install in a VMware default Windows 98 configured Virtual Machine and if it doesn't then as already mentioned about the .vmx configuration file, however DO NOT post the contents into the body of the reply, rather attach it as a file.
Note: Use the "Use advanced editor" link in the upper right corner of the normal reply window to bring up the Advanced Editor where you'll be able to attach files via the Choose File button or Browse button (depending on the Browser) above the Post Message button!