I cannot understand what this error means, but it shows up every time I use Mod Manager no matter how many or how few mods I have active.

Exception in custom XML loader for ModManager.Incompatible. Node is:
<li>Better Spots</li>

Exception is:
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.ArgumentException: Invalid version string: "Spots"
at SemVer.PartialVersion..ctor (System.String input) [0x00057] in <8c87131465e248beb5222f2df5b3eafb>:0
at SemVer.Comparator..ctor (System.String input) [0x00069] in <8c87131465e248beb5222f2df5b3eafb>:0
at SemVer.Comparator.TryParse (System.String input) [0x00033] in <8c87131465e248beb5222f2df5b3eafb>:0
at SemVer.ComparatorSet..ctor (System.String spec) [0x000ce] in <8c87131465e248beb5222f2df5b3eafb>:0
at SemVer.Range+<>c.<.ctor>b__2_0 (System.String s) [0x00000] in <8c87131465e248beb5222f2df5b3eafb>:0
at System.Linq.Enumerable+SelectArrayIterator`2[TSource,TResult].ToArray () [0x00012] in <351e49e2a5bf4fd6beabb458ce2255f3>:0
at System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x0001f] in <351e49e2a5bf4fd6beabb458ce2255f3>:0
at SemVer.Range..ctor (System.String rangeSpec, System.Boolean loose) [0x00049] in <8c87131465e248beb5222f2df5b3eafb>:0
at ModManager.VersionedDependency.LoadDataFromXmlCustom (System.Xml.XmlNode root) [0x0003b] in <493fbfcbeef84e44a8e3d825159b380f>:0
at (wrapper managed-to-native) System.Reflection.MonoMethod.InternalInvoke(System.Reflection.MonoMethod,object,object[],System.Exception&)
at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00032] in <567df3e0919241ba98db88bec4c6696f>:0
--- End of inner exception stack trace ---
at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00048] in <567df3e0919241ba98db88bec4c6696f>:0
at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <567df3e0919241ba98db88bec4c6696f>:0
at Verse.DirectXmlToObject.ObjectFromXml[T] (System.Xml.XmlNode xmlRoot, System.Boolean doPostLoad) [0x00087] in <7927e938de4c4089b4add4215e58d5b1>:0
Verse.Log:Error(String, Boolean)
Verse.DirectXmlToObject:ObjectFromXml(XmlNode, Boolean)
Verse.DirectXmlToObject:ListFromXml(XmlNode)
Verse.DirectXmlToObject:ListFromXmlReflection(XmlNode)
Verse.DirectXmlToObject:ObjectFromXml(XmlNode, Boolean)
Verse.DirectXmlToObject:ObjectFromXmlReflection(XmlNode, Boolean)
Verse.DirectXmlToObject:ObjectFromXml(XmlNode, Boolean)
Verse.DirectXmlLoader:ItemFromXmlString(String, String, Boolean)
Verse.DirectXmlLoader:ItemFromXmlFile(String, Boolean)
ModManager.Manifest:For(ModMetaData)
ModManager.ModButton_Installed:get_Manifest()
ModManager.ModButton_Installed:get_Requirements()
ModManager.ModButton:get_RelevantIssues()
ModManager.ModButton:DoModIssuesIcon(Rect)
ModManager.ModButton_Installed:DoModButton(Rect, Boolean, Action, Action, Boolean, String)
ModManager.Page_BetterModConfig:DoAvailableMods(Rect)
ModManager.Page_BetterModConfig:DoWindowContents(Rect)
Verse.Window:InnerWindowOnGUI(Int32)
UnityEngine.GUI:CallWindowDelegate(WindowFunction, Int32, Int32, GUISkin, Int32, Single, Single, GUIStyle)