NPE in Page template wizard

I tried to pick a template for my page. I clicked on the link, got the
list of possible templates (there was only 1), selected it, then clicked
Next. That's when I got this stacktrace.

ause:
java.lang.NullPointerException

Stack Trace: [hide]

java.lang.NullPointerException
at java.util.regex.Matcher.getTextLength(Matcher.java:758)
at java.util.regex.Matcher.find(Matcher.java:414)
at
com.atlassian.confluence.pages.templates.DefaultPageTemplateManager.getTemplateVariables(DefaultPageTemplateManager.java:92)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at
org.springframework.aop.framework.AopProxyUtils.invokeJoinpointUsingReflection(AopProxyUtils.java:59)
at
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:201)
at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
at
com.atlassian.confluence.util.profiling.SpringProfilingInterceptor.invoke(SpringProfilingInterceptor.java:17)
at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:196)
at
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:154)
at
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:196)
at
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:135)
at $Proxy17.getTemplateVariables(Unknown Source)
at
com.atlassian.confluence.pages.actions.PageVariablesAction.getTemplateVariables(PageVariablesAction.java:25)
at
com.atlassian.confluence.pages.actions.PageVariablesAction.execute(PageVariablesAction.java:33)
at
com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:171)
at
com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:37)
at
com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:168)
at
com.opensymphony.xwork.interceptor.DefaultWorkflowInterceptor.intercept(DefaultWorkflowInterceptor.java:58)
at
com.atlassian.confluence.core.ConfluenceWorkflowInterceptor.intercept(ConfluenceWorkflowInterceptor.java:32)
at
com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:168)
at
com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:37)