I have just installed v2.3.2 on XAMPP for Windows Version 1.7.1 and after logging into CMS instead of the site editor I got this warning screen (below). If someone can help me to get round this problem I would really appreciate it as I would love to improve my current website.

[Warning] Invalid argument supplied for foreach()
GET /SilverStripe/admin/

Line 174 in C:\xampp\htdocs\SilverStripe\sapphire\core\model\Hierarchy.php
Source

165       }
166    }
167    
168    /**
169     * Ensure marked nodes that have children are also marked expanded.
170     * Call this after marking but before iterating over the tree.
171     */
172    protected function markingFinished() {
173       // Mark childless nodes as expanded.

174       foreach($this->markedNodes as $id => $node) {

175          if(!$node->isExpanded() && !$node->numChildren()) {
176             $node->markExpanded();
177          }
178       }
179    }
180    

Trace

* Hierarchy->markingFinished()
* call_user_func_array(Array,Array)
Line 489 of Object.php
* Object->__call(markingFinished,Array)
* Forum->markingFinished()
Line 286 of Forum.php
* Forum->getChildrenAsUL(, "<li id=\"record-$child->ID\" class=\"" . $child->CMSTreeClasses($extraArg) . "\">" . "<a href=\"" . Director::link(substr($extraArg->Link(),0,-1), "show", $child->ID) . "\" class=\"" . $child->CMSTreeClasses($extraArg) . "\" title=\"Page type: ".$child->class."\" >" . ($child->TreeTitle()) . "</a>" ,CMSMain,1,AllChildrenIncludingDeleted,)
Line 56 of Hierarchy.php
* Hierarchy->getChildrenAsUL(, "<li id=\"record-$child->ID\" class=\"" . $child->CMSTreeClasses($extraArg) . "\">" . "<a href=\"" . Director::link(substr($extraArg->Link(),0,-1), "show", $child->ID) . "\" class=\"" . $child->CMSTreeClasses($extraArg) . "\" title=\"Page type: ".$child->class."\" >" . ($child->TreeTitle()) . "</a>" ,CMSMain,1,AllChildrenIncludingDeleted,)
* call_user_func_array(Array,Array)
Line 489 of Object.php
* Object->__call(getChildrenAsUL,Array)
* ForumHolder->getChildrenAsUL(, "<li id=\"record-$child->ID\" class=\"" . $child->CMSTreeClasses($extraArg) . "\">" . "<a href=\"" . Director::link(substr($extraArg->Link(),0,-1), "show", $child->ID) . "\" class=\"" . $child->CMSTreeClasses($extraArg) . "\" title=\"Page type: ".$child->class."\" >" . ($child->TreeTitle()) . "</a>" ,CMSMain,1,AllChildrenIncludingDeleted,)
Line 56 of Hierarchy.php
* Hierarchy->getChildrenAsUL(, "<li id=\"record-$child->ID\" class=\"" . $child->CMSTreeClasses($extraArg) . "\">" . "<a href=\"" . Director::link(substr($extraArg->Link(),0,-1), "show", $child->ID) . "\" class=\"" . $child->CMSTreeClasses($extraArg) . "\" title=\"Page type: ".$child->class."\" >" . ($child->TreeTitle()) . "</a>" ,CMSMain,1,AllChildrenIncludingDeleted)
* call_user_func_array(Array,Array)
Line 489 of Object.php
* Object->__call(getChildrenAsUL,Array)
* SiteTree->getChildrenAsUL(, "<li id=\"record-$child->ID\" class=\"" . $child->CMSTreeClasses($extraArg) . "\">" . "<a href=\"" . Director::link(substr($extraArg->Link(),0,-1), "show", $child->ID) . "\" class=\"" . $child->CMSTreeClasses($extraArg) . "\" title=\"Page type: ".$child->class."\" >" . ($child->TreeTitle()) . "</a>" ,CMSMain,1,AllChildrenIncludingDeleted)
Line 523 of LeftAndMain.php
* LeftAndMain->getSiteTreeFor(SiteTree)
Line 160 of CMSMain.php
* CMSMain->SiteTreeAsUL()
* call_user_func_array(Array,Array)
Line 408 of ViewableData.php
* ViewableData->XML_val(SiteTreeAsUL,,1)
Line 294 of .cacheC..xampp.htdocs.SilverStripe.cms.templates.Includes.CMSMain_left.ss
* include(C:\Documents and Settings\Owner\Local Settings\Temp\silverstripe-cacheC--xampp-htdocs-SilverStripe\.cacheC..xampp.htdocs.SilverStripe.cms.templates.Includes.CMSMain_left.ss)
Line 354 of SSViewer.php
* SSViewer->process(CMSMain)
Line 773 of ViewableData.php
* ViewableData->renderWith(Array)
Line 480 of LeftAndMain.php
* LeftAndMain->Left()
* call_user_func_array(Array,Array)
Line 408 of ViewableData.php
* ViewableData->XML_val(Left,,1)
Line 59 of .cacheC..xampp.htdocs.SilverStripe.cms.templates.LeftAndMain.ss
* include(C:\Documents and Settings\Owner\Local Settings\Temp\silverstripe-cacheC--xampp-htdocs-SilverStripe\.cacheC..xampp.htdocs.SilverStripe.cms.templates.LeftAndMain.ss)
Line 354 of SSViewer.php
* SSViewer->process(CMSMain)
Line 175 of Controller.php
* Controller->handleAction(HTTPRequest)
Line 129 of RequestHandler.php
* RequestHandler->handleRequest(HTTPRequest)
Line 122 of Controller.php
* Controller->handleRequest(HTTPRequest)
Line 277 of Director.php
* Director::handleRequest(HTTPRequest,Session)
Line 121 of Director.php
* Director::direct(/admin/)
Line 118 of main.php

Thank you Sam for the suggestion.

After my post I discovered that it was the Forum module that was at fault, it was version o.1. I had included both the blog and forum modules in the initial install. So I reinstall SilverStripe without the Forum module and had no problems starting the CMS. I'll now download the latest version of the Blog and Forum and have a play. I am looking forward to seeing what I can develop.

Again thanks.