Connection problem when adding sites and dns records

I'm trying to add several sites (each having 1 Zone, 4 A-records, 4 NS-records and 1 MX-record), but sometimes couple of these will fail.
Sites that I'm trying to add are identical in almost every way. Only difference usually is top level domain (com, net, info etc.).

Here is how this process goes:

Loop each site {

login;
dns_zone_add;
dns_a_add; (x4)
dns_mx_add;
dns_ns_add; (x4)
sites_web_domain_add;
logout;​

}

Failure might occur at any phase of this process.

Here are some of the errors I have receive:

• SoapClient::__doRequest() [soapclient.--dorequest]: SSL: Connection reset by peer
• SoapClient::__doRequest() [soapclient.--dorequest]: Failed to enable crypto
• SoapClient::__doRequest() [soapclient.--dorequest]: connect() failed: Unspecified error
• SoapClient::__doRequest() [soapclient.--dorequest]: connect() failed: Connection refused

EDIT:
Here is some more information.
Adding zone failed right after successful login and SOAP faultstring contained this: "The Session is expired or does not exist." How is this possible?
Another faultstring for some other add failure contained: Could not connect to host.

This problem seems to only affect adding. Getting stuff works like a charm.

Any help is appreciated.