Martin,
Keep in mind that when you apply an acl like this, it allows any external user to access host x.x.x.x on port x. It blocks ALL other traffic, including return traffic.
You need to identify other traffic which you want to permit, including return traffic (very typical is dns replies, icmp traffic, established tcp traffic, etc).
Consider temporarily modifying your ACL as follows:
permit tcp any host x.x.x.x 255.255.255.255 eq x
permit tcp any any log
permit udp any any log
permit icmp any any log
permit ip any any log
Then, enable "logging on" and logging buffer debug" and do a show log and see what traffic you normally permit, then allow the desired portion of that traffic. Once you have the majority of that traffic identified, then you can remove the extra permit statements, and consider temporarily putting a "deny ip any any log" to see what else you might be missing.
Once you're done tuning, then remove all the extraneous lines.
HTH
Jeff
