Errors while encoding

[qk7-9z3dbt3ymbe6sm-]

Hello everyone,

i'm trying do encoding a drupal project using ZendGuard 5.5.0 and php 5.3, it seems to work but while encoding i get some errors:

print_pdf.class_php4.inc(line 24): Cannot re-assign $this
Encoding of '/home/sites/assiweb/modules/acquia/print/print_pdf/print_pdf.class_php4.inc' failed - ignoring....
advcache.install(line 238): Cannot redeclare advcache_update_1() (previously declared in advcache.install:58)
Encoding of '/home/sites/assiweb/sites/all/modules/advcache/advcache.install' failed - ignoring....
memcache.php(line 205): Assigning the return value of new by reference is deprecated
AssiwebModel.class.inc(line 8): Static function AssiwebModel::getType() should not be abstract
gmaps_content.views.inc(line 164): Redefining already defined constructor for class gmaps_content_address_fast_filter_helper
gmaps_term.views.inc(line 156): Redefining already defined constructor for class gmaps_term_address_fast_filter_helper
gmaps_user.views.inc(line 153): Redefining already defined constructor for class gmaps_user_address_fast_filter_helper

do you think those errors could cause any kind of problem?
it is a drupal application, is it known that zend guard works with drupal?

thank you for your help.