Application is throwing NSAPI and other errors after the migration

Question

We started seeing NSAPI and other errors after the migration of new codes and recently make some changes
1) During the migration, all the 4 WLS cluster instances were bounced simultaneously. What is the best practice and recommendation from BEA Oracle? Do we need to bounce it one by one for any specific reason?
2) we recently introduced the 4th weblogic cluster instance on Solaris 10 zone. All other WLS instances are running on Solaris 8.
Is it okay to have two different OS versions( Solaris 8 and Solaris 10) and different hardware to host WLS cluster instances? Does BEA Oracle support this kind of configuration?
3) We are consistently seeing below errors in the iplanet web server error logs even though site is working fine
[11/Sep/2009:08:53:50] failure ( 4453): for host XX.XX.XX.XX trying to POST /servlet/FSO, wl-proxy reports: exception occurred for backend host 'YY.YY.YY.YY/23120/0': 'CONNECTION_REFUSED [os error=0, line 1732 of URL.cpp]: Error connecting to host YY.YY.YY.YY.YY:23120'
Do we need to upgrade our WLS proxy plugin? . Current version of WLS proxy plug-in is libproxy_61.so. Our Weblogic version is WLS 92 MP2
I'll really appreciate if some can anwsers those questions

Answer 1

OK booted in to Virtualbox, seems too be working fine this way, maybe it is the ATi drivers
any Help would be appreciated