NullPointerException when removing attachment

java.lang.NullPointerException
at com.atlassian.confluence.pages.AttachmentUtils.getContainingFolder(AttachmentUtils.java:35)
at com.atlassian.confluence.pages.DefaultAttachmentManager.removeAttachmentFromServer(DefaultAttachmentManager.java:97)
at com.atlassian.confluence.pages.DelegatorAttachmentManager.removeAttachmentFromServer(DelegatorAttachmentManager.java:59)
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)